Beta 38hp Engine Has Stopped Heating Hot Water

[PaulN]

On 06/10/2022 at 15:11, MargeandParge said:

Hi Paul 

Check your feed and return hoses right through as they are normally half inch heater hose and can collapse or kink when bent. 

No jokes about kink and bent in the same sentence please . 

Kindest Regards 

Marge and Parge 

Thanks Marge & Parge, but my system is rigid heat resistant plastic, not hoses. Only very short length of hose at engine junctions of about 150mm, which are fine.

Attached is a photo of the type of pipework, it shows the cold water system but I'm at home and don't have a photo of the hot water system, but it is the same.

[PaulN]

7 hours ago, BroadAmbition said:

Just for interest why can you just take off the Radiator Cap with the engine running at a fair speed and get the Air lockout that way?

You can when the engine is cold started, blipping the throttle and hand squeezing a flexi coolant pipe helps (If there is one) but you need to have the cap in hand ready for when the thermostat opens and the coolant starts to expand

Griff

Thanks Griff. With the cap off of the top up reservoir starting from cold and running the engine up to temperature, there is no apparent increase in the level which is about 50mm below the filler cap 

[PaulN]

5 hours ago, Smoggy said:

Try taking the cap off when up to temperature and you are likely to get a face full of scalding coolant, I know of a guy that did just that and had skin falling off his face.

Cold there's usually air in the header anyway, in a perfect system air will always get back to the header but perfect systems are a big ask on a boat.

Hi Smoggy. I can take the cap off when hot and nothing shoots out

[PaulN]

4 hours ago, Vaughan said:

Please beware!   The Nanni and Beta have a pressurised cooling system which is not the same as the good old Perkins or BMC.

This is one of the main reasons why hire boat companies these days do not even "lift the floorboards" when giving a trial run to customers.  They simply say "if it overheats, stop the boat at once and call the boatyard".

On the other hand, and as ANNV describes, you can use the pressure in the system to blow an airlock out of the calorifier pipes, by simply easing the right Jubilee clip and bleeding the air out, while the engine is running at normal temperature - and pressure.

Please NEVER take the pressure cap off the heat exchanger or expansion chamber of a Nanni or Beta engine when it has just been running and is up to its normal temperature.

Hi Vaughan. As you will see from the earlier photo, I can slacken the joints in the pipework which I have done close to the engine and the top joint and the calorifier.

I can take the cap of the filler when the engine is up to temperature and no problem, is that significant to the HW system problem do you think?

[PaulN]

4 hours ago, annv said:

Hi Paul the water flow is pumped around the engine by a impeller ie water pump the flow to the califora comes from the rear of the had through califora and back to the water pump housing if not getting hot it is because the pipes are blocked or the thermostat is in the open fail position this wont stop engine getting hot but will take longer as the water flows through the heat exchanger constantly remove cap remove hose from califora does the water pour out if yes remove return does water flow from califora .if it flows your problem is the thermostat. John 

John

As I said above with photo, the hoses can't be blocked by any form of collapse and disconnecting the pipe at the top of the calorifier circuit only produces a slight trickle of water. Therefore perhaps it is a thermostat problem, albeit the engine gets to 75 deg C in about 10 minutes. Perhaps I should get a new stat and take it with me when I go to the boat in a weeks time. If when I take the stat out with engine cold and find it is closed, then I presume it isn't the problem. Thank you for your help.

[PaulN]

1 hour ago, Smoggy said:

Be aware John means the engine water pump not the raw water pump, easily to get confused if you're not mechanically minded, they both have impellors just different types (the raw water is the one you change regularly).

Thanks Smoggy. I am aware yes. Fairly conversant with engines, having played around with them on my cars back in the early 70's. But a good point and all help is greatly appreciated 

[Vaughan]

This is all getting a bit confused and I think we need to get back to basics.

The photo you have shown us is the domestic fresh water pipework, which all looks very well installed and new. This circuit, however, will not be connected to the engine.  The calorifier tank will have 4 connections : two will be in plastic pipe as your photo and will be the cold water feed on the bottom (with a non return valve) and the hot water outlet at the top, where there will also be (I hope) a pressure relief valve.

There will be two further hoses, possibly marked as "car heater hose" since they need to be of hot water quality.  The heating of the calorifier works in exactly the same way as  the heater circuit in a car.  Hot water is passed from somewhere on the cylinder head (the hottest part of the engine) to the bottom of the calorifier tank - on the principle of convection, that hot water rises.

This circuit is pushed by the internal water pump - or "circulating pump" of the engine, which is just the same as on the engine in your car.  The "raw" water pump (with a rubber impellor), which passes river water through the heat exchanger, is not involved in this!  Your car is cooled by a radiator fan, but your boat is cooled by river water through a heat exchanger.  The return circuit from the calorifier to the engine must go to somewhere "in front" of the "circ pump" and this is usually a T connection on the pipe leading up from the bottom of the block to the circ pump.

In most boats, the calorifier tank is installed in the bilges slightly above the engine, because of the curve of the hull, so this can create an air lock in the circuit.  With the engine running at normal temperature and with the pressure caps closed, ease off the jubilee clip on the pipe going from the cylinder head to the bottom of the tank, at the engine end. The pressure in the cooling system system will then force air out of the pipes.

If this does not work the first time, let the engine cool down, top up the coolant in the header tank and try again.  This is because if you have a lot of air in the pipes, you may drop the coolant too low in the header tank.

I hope this makes sense.

I think I need a glass of wine now . . . . 

[Smoggy]

You keep mentioning the top pipe on the calorifier, is it a vertical or horizontal calorifier? Usually the top pipe is not coolant but hot water to taps with bottom pipe being cold water in from tank, the coil itself are usually in between that link to the engine coolant.

Sorry if this makes no sense and is no help but it's friday afternoon and I've been to the pub.... (purely for a practice you understand, I'll be back later for the proper job )

I wouldn't want rigid pipe and pushfit fittings on my coolant side, I do have them on my domestic hot water side.

[annv]

Hi Paul you have Hep-2-O water pipes in your picture, very good for hot and cold feeds to taps/shower etc BUT should not be connected directly  to the engine as they have no give and  will transmit noise / vibration and will fracture over time with vibration, there should be a plastic or rubber hose that connects directly to the engine this  will absorb the noise and vibration from the engine. John

[PaulN]

20 hours ago, Vaughan said:

This is all getting a bit confused and I think we need to get back to basics.

The photo you have shown us is the domestic fresh water pipework, which all looks very well installed and new. This circuit, however, will not be connected to the engine.  The calorifier tank will have 4 connections : two will be in plastic pipe as your photo and will be the cold water feed on the bottom (with a non return valve) and the hot water outlet at the top, where there will also be (I hope) a pressure relief valve.

There will be two further hoses, possibly marked as "car heater hose" since they need to be of hot water quality.  The heating of the calorifier works in exactly the same way as  the heater circuit in a car.  Hot water is passed from somewhere on the cylinder head (the hottest part of the engine) to the bottom of the calorifier tank - on the principle of convection, that hot water rises.

This circuit is pushed by the internal water pump - or "circulating pump" of the engine, which is just the same as on the engine in your car.  The "raw" water pump (with a rubber impellor), which passes river water through the heat exchanger, is not involved in this!  Your car is cooled by a radiator fan, but your boat is cooled by river water through a heat exchanger.  The return circuit from the calorifier to the engine must go to somewhere "in front" of the "circ pump" and this is usually a T connection on the pipe leading up from the bottom of the block to the circ pump.

In most boats, the calorifier tank is installed in the bilges slightly above the engine, because of the curve of the hull, so this can create an air lock in the circuit.  With the engine running at normal temperature and with the pressure caps closed, ease off the jubilee clip on the pipe going from the cylinder head to the bottom of the tank, at the engine end. The pressure in the cooling system system will then force air out of the pipes.

If this does not work the first time, let the engine cool down, top up the coolant in the header tank and try again.  This is because if you have a lot of air in the pipes, you may drop the coolant too low in the header tank.

I hope this makes sense.

I think I need a glass of wine now . . . . 

Vaughan, thank you again for your input and help. 

Yes the installation is all very neat, albeit the boat is 14 years old. I understand how all the systems work (or don't as the case maybe), but thank you as I do realise that many people may not. Both hot and cold systems are plumbed in with the same pipework throughout, except for a 2 short lengths of rubber  connecting the HW flow and return to the 2 engine spiggiots. (photo from manual attached).

The tank is a small (though large for a broads boat) domestic copper water cylinder factory encased with a bonded on polystyrene insulation jacket installed in an airing cupboard, i.e. slatted shelving above. All 4 connections are the same type of pipework going straight on to the cylinder spiggots and there is a pressure release valve.

I've tried so many things that it is difficult to remember what order I did them, but what you say seems to make a lot of sense, i.e. with pressure cap on, slacken off the HW return at the engine and then run the engine which must surely purge the system. I'm back at the boat next weekend, so will let you know how I get on.

[PaulN]

20 hours ago, Smoggy said:

You keep mentioning the top pipe on the calorifier, is it a vertical or horizontal calorifier? Usually the top pipe is not coolant but hot water to taps with bottom pipe being cold water in from tank, the coil itself are usually in between that link to the engine coolant.

Sorry if this makes no sense and is no help but it's friday afternoon and I've been to the pub.... (purely for a practice you understand, I'll be back later for the proper job )

I wouldn't want rigid pipe and pushfit fittings on my coolant side, I do have them on my domestic hot water side.

Thanks Smoggy, yes, I fully understand the plumbing principles and what the 4 connections are for, though realise this may not have been evident. They are not push fittings but plastic threaded compression fittings and are completely sealed, the coolant level never drops.

 

[PaulN]

3 hours ago, annv said:

Hi Paul you have Hep-2-O water pipes in your picture, very good for hot and cold feeds to taps/shower etc BUT should not be connected directly  to the engine as they have no give and  will transmit noise / vibration and will fracture over time with vibration, there should be a plastic or rubber hose that connects directly to the engine this  will absorb the noise and vibration from the engine. John

Hi John. Yes there is a short length of rubber about 150mm where the pipes join the engine.

[MargeandParge]

Hi Paul

Had anything different happened before it stopped working ie service or winterisation ?

regards Marge and Parge

[MargeandParge]

A simple thing that I would do you will lose your antifreeze is take the feed and return off the engine and connect a hose to the feed, one of those small spray nozzles fits inside your flexi pipes to the engine and with low pressure see if you have a  flow through the calorifier coil tube. It is a process of elimination.

Kindest Regards

Marge and Parge3

[Vaughan]

12 hours ago, PaulN said:

i.e. with pressure cap on, slacken off the HW return at the engine and then run the engine which must surely purge the system.

Just one thing : Run the engine up to normal temperature first, then you have pressure in the system, with thermostat open.

The calorifier sounds like the classic and very reliable type which were supplied to hire fleets by Coopers in Gt Yarmouth. I usually do the bleeding from the engine end, as the calorifier is not always easily accessible, with the engine running! The obvious place to do it would be where the topmost engine pipe leaves the calorifier.

[PaulN]

18 hours ago, MargeandParge said:

A simple thing that I would do you will lose your antifreeze is take the feed and return off the engine and connect a hose to the feed, one of those small spray nozzles fits inside your flexi pipes to the engine and with low pressure see if you have a  flow through the calorifier coil tube. It is a process of elimination.

Kindest Regards

Marge and Parge3

Thanks Marge & Parge. I will try Vaughan's latest suggestion first as it will save the antifreeze, but if I still can't get it to flow, I will do as you suggest.

[PaulN]

6 hours ago, Vaughan said:

Just one thing : Run the engine up to normal temperature first, then you have pressure in the system, with thermostat open.

The calorifier sounds like the classic and very reliable type which were supplied to hire fleets by Coopers in Gt Yarmouth. I usually do the bleeding from the engine end, as the calorifier is not always easily accessible, with the engine running! The obvious place to do it would be where the topmost engine pipe leaves the calorifier.

Thank's Vaughan. I can get to the top calorifier pipe of the engine coolant circuit, which I tried, but not sure if I had the engine up to temperature, so will give it another go when I go to the boat next weekend. I presume with the pressure cap on?

[annv]

Hi If you are getting flow to the calorifier but it's cold or warm its the thermostat if no flow it has a blockage/air lock, or worn pump vanes, (very unlikely). John

[PaulN]

Thanks for everyone's help on this subject, now for the update:

I tried everything, cracking open the flow and return pipes at the calorifier to vent any air locks and the same at the engine, each time with engine running, but still the return at the engine ran cold. I ruled out the thermostat as the engine would overheat if jammed shut.

Having just had 10 days on the boat ending yesterday. Halfway through, having both had showers and and washed the breakfast things, there was little hot water left. We cruised from Ranworth to Womack and I noticed that for the first half of the journey the engine temperature was about 5 degrees lower than usual at just over 70 degrees C. When we arrived at Womack the water was piping hot. This has carried on since.

Don't really know why this suddenly happened, perhaps using the immersion heater a few days running when plugged into shore power  had the reverse effect and heated the glycol/water coil in the tank, expanding it and 'unblocking' any trapped air bubble. Not sure if that could be the case, but it's all stayed working since, so very pleased   

[Regulo]

Just the sort of fault I hate - the one that disappears on it's own. Always on tenterhooks it'll come back.

[annv]

Hi Thermostats usely fail in open position, ie fail/safe. John

[Smoggy]

So the hot water fairy strikes again!

At least it's playing the game now.

[MargeandParge]

8 hours ago, Smoggy said:

So the hot water fairy strikes again!

At least it's playing the game now.

Recon he got a lead long enough to reach Womac from Ranworth and stayed plugged in with the immersion still on 

Kindest Regards Marge and Parge