W210 300td very poor heater

[Frontstep]

I'm glad you put that I was getting confused.

 

[Ian Parkin]

Different layout to a 606 engine two pipes go to the duo valve and two pipes out and the pipe supplying hot to the duo valve doesn't come from the mechanical water pump .. It needs the electrical pump to supply hot water

 

[Dec]

RichardM98 fails to stat the purpose of this electric pump and fails to state that the engine is off when it’s in use.
Why would there be a need for an electric circulation pump running while there is a mechanical engine pump running while the car is being driven.

There doesn’t seem to be any other explanation other than stuck duo valves… has the car been unused for a very long time?

Dec

 

[Dec]

Any chance of picturs Ian, thats a difrent kettle of fish.

Dec

 

[Ian Parkin]

I use the car every day just recently noticed that there was no heat ....I,m not saying yet that the duo valve is perfect but would both sides fail at the same time? The two pipes feeding the valve one in and one out never get hot or have flow in them as evidenced by placing a clear section of pipe in feed pipe with engine running or indeed having pipe off whilst running nothing comes out.

I,ve done 90,000 in the car since I've had it

 

[Ian Parkin]

The duo valve is the same layout as the pic you posted which I presume wasn't your pic as your car only has one input pipe? Was the pic POD,s

 

[Dec]

what is POD?

Dec

 

[Dec]

When duo valves fail, electrically, then the should fail in the open position which results in heat all the time… that was the thinking in unplugging the power supply so you would have heat, but the thinking here is that the valves are stuck, both at the same time? could be, a bit unusual but possible I suppose.

That diagram above represents how my heating works without the need for the electric pump if the engine is running, however you seem to have a different set up, an extra tube, what I can’t get my head around is why you would need an electric pump when you have a mechanical engine pump while the car is being driven… I understand the need for an electrical pump when the engine is off to use the residual heat still in the engine.

Hopefully your new pump will cure the fault, if not then it has to be stuck valves.

Dec

 

[Ian Parkin]

pOD is parrot of doom

 

[Dec]

The duo valve is the same layout as the pic you posted which I presume wasn't your pic as your car only has one input pipe? Was the pic POD,s

Parrot of doom, of course, I feel like an eejit now. The picture/drawing is of a C180 w202, not PODs and was in relation to a different fault relating to the heating, see… http://forums.mercedesclub.org.uk/showthread.php?t=75631&highlight=Recirculation … not sure what car POD is referring to.

I unplugged my recirculation pump this morning to see if I would lose my heating, its disconnection made no difference to the heating, everything was normal, whether I was moving or when stationary with the blower on full blast.

However we are talking different cars and you seem to have a different set up with the tubes, in my case, the recirculation pump plays no part in circulating the water through the heating system while the engine is running.

Dec

 

[Frontstep]

I thought the electric pump was to ensure even cooling after switching off.
This fitment allows the rest facility.

 

[Ian Parkin]

Yes it does run on apparently but also on a 606 engine it has to run at all times when you are calling for heat.

Does yours run all the time frontstep?
hopefully when the new pump arrives it will solve the problem
hopefully monday

ian

 

[Dec]

I thought the electric pump was to ensure even cooling after switching off.
This fitment allows the rest facility.

I’ve herd mention of that, that could be another aspect to the pump alright, I’ve never noticed it coming on after a drive, it is extremely quiet in operation, it might not do that on a W202.

Dec

 

[Frontstep]

I had another link to a heater and Duovalve problem thats worth a look it has a canny fix for the valves and explains the lead up.
This is a great post from the states ;
http://www.peachparts.com/shopforum...-w210-got-my-heat-back-saved-myself-$250.html

 

[Ian Parkin]

Thanks for that frontstep
though as he says only the e300 and 420 have the 2 inlet duovalve and the running circulation pump as even without the pump(taken out and bypassed) i have very little hot water going through the pipes ( only thermosyphoning) I'm confidant that a new pump will sort it and theres nothing wrong with the duovalve

 

[Frontstep]

I kept it in my favourites as it made sense and was clear.

 

[Ian Parkin]

All toasty now with new circulation pump fitted

 

[amkahal]

I have the same problem

Hi, i am new to the forum.

i'm facing the same problem on E230 1997 M111, the recirculating pump is running but when i unplug the hose (from pump to duo valve) there is no water flow at all, so can the pump be faulty ?

sorry for my bad english.