Water temperature sender part number?

[paddler1]

My engine seems to be a lot happier now thanks to your sound advice. I have added the extra wire too to the oil gauge and all seems to be reading as you correctly predicted.

i have cleaned out the bilge and now I have final question - when the engine is running I have noticed a very small trickle of clear water coming out off a drain pipe that is connected to the bottom of the calorifier (red cap) - is this just normal as the calorifier is pressured? I have never dared touch the red cap but it does turn and add ‘water’ I guess to get the right pressure? No gauge for my to worry about tho?

[Tracy D'arth]

8 minutes ago, paddler1 said:

My engine seems to be a lot happier now thanks to your sound advice. I have added the extra wire too to the oil gauge and all seems to be reading as you correctly predicted.

i have cleaned out the bilge and now I have final question - when the engine is running I have noticed a very small trickle of clear water coming out off a drain pipe that is connected to the bottom of the calorifier (red cap) - is this just normal as the calorifier is pressured? I have never dared touch the red cap but it does turn and add ‘water’ I guess to get the right pressure? No gauge for my to worry about tho?

That sounds like a pressure release valve venting due to the lack of an expansion vessel on the hot water system. Or it has a vessel which has no air pressure inside, gone flat.

Needs fixing as it will erode the seat eventually and you will have a continuous leak.

The water expands when heating and the excess pressure has to go somewhere.

[springy]

The Red cap is your Pressure Relief Valve (PRV), as the water in the calorifier heats up it expands - this could burst it if it rises too high so the PRV should vent any excess. They are notorious for dribbling - sometimes it is just crud on the seat and rotating the red cap a few times will cause the valve to open and clear the crud. If the domestic water pump has been changed it could be running at a higher pressure then it would also cause the PRV to vent. If there is no Expansion Vessel fitted (not to be confused with an Accumulator - which may be identical in appearance) then this could also cause the PRV to vent. The top of the red cap should be marked with its set pressure - often 3.5 bar, but it should be matched to the calorifier design pressure.

 

springy

[Tony Brooks]

That is a PRV that is venting as the engine heats the water in the calorifier causing it to expand. It means that you either do not have an expansion vessel plumbed into the domestic water system or if you have t has lost all its pressure.  To save stressing the calorifier you really need one.

 

The calorifier is pressurized to the domestic water pump cut out pressure.

 

You do not add water that way. The domestic water pump does that. If you twist the red cap it will click and water will spurt out and hopefully wash any crud off the valve seat - if it needs doing

[paddler1]

I haven’t changed any water pumps?

it seems to have only started to dribble since I had the engine cylinder head refurbished last week, they also put in a new thermostat and the cooling system has been bled for air blockages using the tap on the top of the skin tank.

i didn’t do anything to bleed any air from the calorifier

i have now noticed that the calorifier seems to heat up the hot water a bit quicker now too.

So when I give the red cap a turn then I can hear air escaping and the pump kicks in?

is this correct?

[Tony Brooks]

Not if it really is air. I think it will be water. If the old thermostat was opening early or jammed open then the engine will run much hotter now so put more heat into the hot water. that will make it expand more.

 

Forget air in the calorifier, eventually t will come out of the hot taps if there is any in there.

 

Water venting form that PRV means one of:

 

The water pump pressure too high

No expansion vessel to accept the expanding water

An expansion vessel with no air in it.

Faulty valve.

 

Two and three are the most likely.