Red Valve On Top Of Calorifier

[annv]

Hi Do you know which of your hoses that go to the calorifier comes from water pump this should go to the bottom connection difficult to see this from you picture it looks like it is on the side ref turn tank 90*??. what do all the hoses do/go to. John

[Ray]

1 minute ago, dnks34 said:

did you do it whilst the engine was running and hot?  If you undo it slowly water ought to be forced out under pressure.  

The engine was running but it hadn't warmed up, next time I'll run for a while first!

[annv]

Ray water will only come out if coolant is under pressure with cap on and engine hot (not recommended) or if header tank cap is removed and as it is higher then engine you dont need to run it. John

[Ray]

5 minutes ago, annv said:

Hi Do you know which of your hoses that go to the calorifier comes from water pump this should go to the bottom connection difficult to see this from you picture it looks like it is on the side ref turn tank 90*??. what do all the hoses do/go to. John

In my photo the hose that is numbered 1 goes from the water pump housing to the top of the 2 fittings on the calorifier.

The calorifier is lying horizontal but appears to be intended that way as the two engine connections lie one above the other on the right hand side of the tank and the red release valve is at the top middle of the long side.

[Meantime]

Ray, the line for the number 2 hose virtually points to where your temperature sender unit is. The nut just next to it can be loosened and used to bleed the system. If you loosen it when the engine is cold you should get water weeping out, if not there is an airlock and your engine is reading that it is not getting fully warm, because the coolant is not reaching the sender unit, which is on the side of that housing.

[dnks34]

2 minutes ago, Meantime said:

Ray, the line for the number 2 hose virtually points to where your temperature sender unit is. The nut just next to it can be loosened and used to bleed the system. If you loosen it when the engine is cold you should get water weeping out, if not there is an airlock and your engine is reading that it is not getting fully warm, because the coolant is not reaching the sender unit, which is on the side of that housing.

This is what I suspect is the case!

[Ray]

1 minute ago, Meantime said:

Ray, the line for the number 2 hose virtually points to where your temperature sender unit is. The nut just next to it can be loosened and used to bleed the system. If you loosen it when the engine is cold you should get water weeping out, if not there is an airlock and your engine is reading that it is not getting fully warm, because the coolant is not reaching the sender unit, which is on the side of that housing.

Got it, that makes good sense. Thank you 👍

[Meantime]

Additionally if you get a short piece of the right diameter hose you can remove hoses 1 and 2 and put a short link in there. Then bleed the system via the nut and the header tank and then run the engine to see how warm it gets. Obviously the calorifier won't get warm as it will no longer be in the circuit, but your engine should run at normal temperature. Once that check is complete then replumb the colorifier back in and bleed again and then check again.

[Smoggy]

My tank has the PRV half way up and the hot outlet right at the top, I'm fairly sure the horizontal calorifier on my old boat was much the same, top fitting should be hot water out, hot water rises and cold sits at the bottom.

70 degrees is plenty as you can scald yourself at 60.

In the pic below the cold goes in the bottom, other bottom (red) is the PRV outlet, hot comes out the top and engine connections go in the two half way up, the link hose is for a thermostatic mixer valve which is the black bit at the top outlet.

It is the right the way up in the pic.

[Meantime]

From the Nanni manual the thermostat should start to open at 69.5 to 72.5 degrees centigrade and be fully open at 85 degrees centigrade. 

When the thermostat is closed the coolant should use the bypass loop which is where the calorifier is connected. Once the thermostat is fully open it will go through the thermostat and therefore not the calorifier, but unless your running the engine flat out over Breydon I don't think you'll reach 85 degrees centigrade and therefore the thermostat will never be fully open and some coolant will also still use the bypass loop through the calorifier.

 

[Ray]

I'm learning so much here you guys are great 👍

I'm going to see if I can get a bit more detail out of the photo of the Calorifier later to try to compare to the above info.

[Meantime]

For reference, in its non marinised state the thermostat would live in the housing where the temperature sender unit is and just above it would be connected one of the radiator hoses. When they are marinised the thermostat is moved to live under that square cover directly below your figure 2 on the heat exchanger and the small bolt is there as one of the bleed points.

[annv]

You should be able to vent the very top of the tank to remove air to reduce Legendar. The pressure relief valve can be fittd any where BUT is usely at the very top so that it can be used to vent tank of air. vertical tanks work best but not always easy to fit a large enough one hence parrilla ones. i would guess that the blue pipe with the nonreturn vale hose goes to the fresh water pump this should go to lowest tank connection. John

[annv]

Hi The large nut on top of the top hose mounting would be for venting the engine, remove header tank cap first, and if you clamp the thin hose from bottom of header tank you can remove/unscrew  the large nut without losing coolant and check that it has a small hole about a third of the way down the treads and it should have a copper washer under the head of the bolt/plug then replace plug finger tight release clamp on small hose unscrew plug until coolant runs out then retighten plug.do not over tighten make sure header tank is kept half full while venting. John

[Ray]

Just for clarification, a clearer idea of the actual hoses on my calorifier -

A. To domestic hot water taps

B. To engine water pump housing. (1)

C. To engine bleed valve housing (2)

D. Cold water in (Fresh water tank then pump then expansion tank) to calorifier.

 

[Smoggy]

Is that pic looking down at it or sideways at it?

[Ray]

5 minutes ago, Smoggy said:

Is that pic looking down at it or sideways at it?

That is sideways so the connections are in that order physically top to bottom.

[Smoggy]

Get yourself an infrared thermometer and follow the coolant pipes with the engine up to temperature and running,  when the temperature drops there's likely air in the hose at that point.

Edit: I'd be looking where the hoses loop up and back down to the engine, with engine cool and off take those hoses off with the expansion tank brimmed and cap off and refit while coolant is coming out and air should clear.

[Oddfellow]

What is the Blue flexible hose on D after the non-return valve? It won't affect your air lock, but it's curious as I can't think what purpose it serves. 

Air locks in calorifier systems can be a real pain, but the easiest way of solving them is to put pressurised water though the whole Calorifier circuit until you get no more air and then reconnect. 

I moved a calorifier about 10 ft further away from an engine many years ago in a refit and suffered hot water issues, so I rigged up a few valves in the system with points that I could put pressurised water though. It made the whole process pretty simple to solve in the event of a problem. 

 

[Ray]

Interesting about the pressurised water, thank you.

As for the blue hose... I'll have to look where it goes next time as I hadn't actually noticed it!

[Meantime]

I would imagine the Blue hose to be the feed from the water pump. I would assume it goes right into the T piece to feed the cold taps and left into the calorifier. This is a similar setup to how mine used to be. I used to find that after a fair bit of engine running that the cold would sometimes run a little warm as hot water expanded back out of the calorifier. I over come this by fitting a non return valve between the cold feed into the calorifier so that hot water couldn't return into the cold circuit. Off course you need to be sure to have a pressure relief valve fitted to the calorifier.

[Ray]

39 minutes ago, Meantime said:

I would imagine the Blue hose to be the feed from the water pump. I would assume it goes right into the T piece to feed the cold taps and left into the calorifier. This is a similar setup to how mine used to be. I used to find that after a fair bit of engine running that the cold would sometimes run a little warm as hot water expanded back out of the calorifier. I over come this by fitting a non return valve between the cold feed into the calorifier so that hot water couldn't return into the cold circuit. Off course you need to be sure to have a pressure relief valve fitted to the calorifier.

That is exactly what I have found 👍

[Islander]

note the addition of an expansion tank if a non return used in cold otherwise hot overpressure valve will bleed when system gets hot.

 

Colin 

[Smoggy]

I would guess blue hose goes to extension tank somewhere, that should stop the prv needing to vent.

[Oddfellow]

The incoming water feed from the pump should be before the non-return valve. The purpose of the valve its to prevent hot water entering the cold water system. If the blue hose runs to the pump, it is in direct contact with the hot water in the calorifier and the additional pressure developed in the tank will have a knock-on effect on the pressure effectiveness of the pump as the pump now has to push against the pressure in the HW system.