No hot water

[NormanStansfield]

My pump started making a noise like an over revving car and it took an hour to heat the water instead 30 minutes. Over the weeks, the noise from the pump got increasingly worse and at the same time it also got to the point that even after an hour the water was lukewarm. The boiler would fire for five to ten minutes then stop but the pump would continue over revving.

The central heating worked fine none of this over reviving or switching off after 5-10 minutes. I got some advice and they changed the three port valve and the hot water still does exactly the same thing but now the central heating has gone off! Since the three port valve was fitted the boiler won't even fire now when the central heating is switched on, this might be a coincidence but whereas the hot water was a slow decline, this was instantaneous.

Now it has been suggested I get a new room thermostat and a new pump but I am getting the destinct impression it is becoming a case of trying different things and seeing if they work but without a clear strategy this seems like an exercise in futility.

My questions are these - could the pump slowly wearing out result in the central heating working but not the hot water? I would have thought both would go at the same time if it was the pump.

Could fitting (or incorrectly fitting) the new three port valve stop the central heating working properly but not affect the hot water (in the sense it is not any worse just not any better)

When the central heating is switched on the boiler now goes from red to flashing green but never to solid green.

Basically I would like to know if a new pump would fix the hot water and a new thermostat will fix the central heating?

 

[terryplumb]

If the pump and central heating worked fine ,and only the hot water circuit was an issue ,then its unlikely the pump was to blame.
As the boiler will not fire for central heating since the three port valve has been replaced ,then the wiring and the three port valve itself are suspect and should be checked out before swapping out other components that apparently worked fine before the valve was changed.

 

[NormanStansfield]

I have got a heating engineer in and the hot water works now. It was the pump, it just needed replacing (if the three port valve had been left alone this would now be sorted).

The heating engineer said the connector box (which is where the three port valve is wired into) is a nightmare as nothing is marked up. Also as someone else (my brother in law) has put in a new three port valve he can't be certain the way it is wired now is the same as it was before (although my brother in law said he did wire for wire, like for like).

The central heating still doesn't come on though unless the hot water has been fulfilled. The heating engineer looked at the room thermostat and claimed a wire was live when it shouldn't be. He said he had removed something that completed the circuit in the room thermostat and without that this wire should not be live but it still was.

He is going to come back with a three port valve to make sure it is not that but what could cause a wire in the room thermostat to be live when it shouldn't be?

 

[Deleted member 267285]

Depends on what’s been tested at the room stat, could be a faulty thermostat, or reversed polarity.

 

[terryplumb]

Things just don't add up here.
You told us in original post that central heating worked fine ,but hot water didn't.
That doesn't indicate a problem with the pump !!

 

[NormanStansfield]

The central heating did work fine. The hot water was the problem, it was taking longer and longer to heat up until it got to the point it was only lukewarm no matter how long it was on for. The boiler kept cutting out etc. This coincided with the pump getting noisier and noiser.

The pump has been replaced and now the boiler doesn't cut out and the water is hot in half hour.

The important part really is that before the pump was replaced the three port valve was replaced first. After that the central heating wouldn't come on at all.

This is the part that concerns me now, the central heating.

If it doesnt make sense that it is the pump that is fine, maybe I am wrong, the main thing about that is the hot water is no longer a problem.

It is the central heating, that is now the issue.

 

[terryplumb]

I fully understand what your current problem is. And it is obvious that changing the pump would not cure the hot water issue and create another problem with the central heating .
Correct me if I am wrong ,but your central heating ,prior to the new pump being fitted ,and with the motorised valve in situ ,worked perfectly well ? Now you are telling us that the motorised valve is a problem ,because the central heating doesn't work ,and it isn't wired properly. Then how did it work before the pump was changed ?

 

[NormanStansfield]

Depends on what’s been tested at the room stat, could be a faulty thermostat, or reversed polarity.

That is interesting regarding the reverse polarity. I got exactly the same three port valve (a Tower one) but the original one had been in at least ten years (since I moved in) probably a lot longer. Could the colour of wires now perform a different function to what they did back then?

 

[NormanStansfield]

I fully understand what your current problem is. And it is obvious that changing the pump would not cure the hot water issue and create another problem with the central heating .
Correct me if I am wrong ,but your central heating ,prior to the new pump being fitted ,and with the motorised valve in situ ,worked perfectly well ? Now you are telling us that the motorised valve is a problem ,because the central heating doesn't work ,and it isn't wired properly. Then how did it work before the pump was changed ?

The new three port valve has caused the issue with the central heating. The boiler no longer fires at all when the central heating is switched on. This only happened after the three port valve was switched. The same old pump was still in and the hot water issue remained the same.

Changing the pump has not created any problems. This was done after the three port valve was changed and now the hot water is working as normal. If anything it has improved things.

I will go over the order of things.

1) Pump sounds like it is wearing out, hot water eventually taking an eternity to even get just lukewarm.

2) Told Brother in Law, he came and had a look and told me he thought it was worth changing the three port valve.

3) He changed three port valve, when the power was put back on central heating didn't work. Hot water exactly the same as it was before the new three port valve was fitted, old pump still in.

4) Binned brother in law for heating engineer, he put a new pump in, hot water now working exactly as it should be. New three port valve still in. Central heating still not working.

That has been the order of things.

I am sorry if things don't add up, I can only describe things that have happened from a layman's point of view and the order that those things have happened.

 

[ianmcd]

Sounds like your new 3 port isnt wired up correctly, some engineer you have that is going to put another valve in to test it that is what a multimeter is for

 

[terryplumb]

The new three port valve has caused the issue with the central heating. The boiler no longer fires at all when the central heating is switched on. This only happened after the three port valve was switched. The same old pump was still in and the hot water issue remained the same.

Changing the pump has not created any problems. This was done after the three port valve was changed and now the hot water is working as normal. If anything it has improved things.

I will go over the order of things.

1) Pump sounds like it is wearing out, hot water eventually taking an eternity to even get just lukewarm.

2) Told Brother in Law, he came and had a look and told me he thought it was worth changing the three port valve.

3) He changed three port valve, when the power was put back on central heating didn't work. Hot water exactly the same as it was before the new three port valve was fitted, old pump still in.

4) Binned brother in law for heating engineer, he put a new pump in, hot water now working exactly as it should be. New three port valve still in. Central heating still not working.

That has been the order of things.

I am sorry if things don't add up, I can only describe things that have happened from a layman's point of view and the order that those things have happened.

Thanks ,this now makes sense . Your earlier posts indicated the central heating worked fine with old pump and new valve ,or I lost the plot !!!
Good luck with it.

 

[NormanStansfield]

Sounds like your new 3 port isnt wired up correctly, some engineer you have that is going to put another valve in to test it that is what a multimeter is for

I don't know. I like the guy. The connector box is a mess. Nothing is marked up and it is a nest of wires. Not being able to see what it originally was like is a handicap as well.

He does have a multimeter, that is how he knows that a wire in the room thermostat has a permanant live.

If you could tell me how he could use his multi meter to determine if it has been wired incorrectly when nothing is marked I would appreciate it, I will definitely pass it on, I just want it sorted. It might be something he is not considering. I have no idea how the wiring of the three port valve could result in a permanant live in the room thermostat and how a multi meter would help him wire it correctly in that situation.

I am guessing he is at the point where he thinks it is worth checking the three port valve is not faulty.

 

[ianmcd]

If you could tell me how he could use his multi meter to determine if it has been wired incorrectly when nothing is marked

same as about 80% of all systems, the only colours you can rely on ina heating system, is the cable from the zone valves that are factory fitted and industry standard colors, you trace everything back from them

 

[Harry Bloomfield]

I don't know. I like the guy. The connector box is a mess. Nothing is marked up and it is a nest of wires. Not being able to see what it originally was like is a handicap as well.

That mess is quite normal, nothing unusual there.

Have you still got the old valve actuator head? Might the wrong model have been fitted?

 

[NormanStansfield]

That mess is quite normal, nothing unusual there.

Have you still got the old valve actuator head? Might the wrong model have been fitted?

I don't have the old one but it was like for like it was a Tower VAL322MP and I got the same one. I took a picture of the back of the old one before I got it taken out. It was the only way I could see what kind it was - by using my phone to reach round and take a picture of the back of it.

The heating engineer I got has given up hahaha. He says there are five wires on the three port valve but only four suitable terminals.

How he has left it is hot water seems to work normally. If you switch on hot water only setting it just heats the water, the radiators stay cold. If I switch on Central heating only setting, it works and the radiators heat up, however it seems once the central heating is satisfied it then goes on to heat the hot water as well. This was very confusing at first because I turned off the heating only setting and switched on the hot water only setting and it wouldn't fire up. At first I thought it just wasn't working at all but now it seems the reason it wasn't switching on is the water was already hot as it gets through the central heating only setting.

Once the hot water is used and is below maximum temperature (like by running a bath) the boiler will power up again on hot water only setting.

I haven't tried both on because the current central heating only setting is sort of both on.

I am disappointed it has been left like this and the little quirks weren't explained but now I have figured them out for myself I can sort of use it.

I figure in the winter even with the heating only setting there will be enough hot water for a bath or shower the next morning (maybe with a little top up on hot water only setting in the morning).

In the summer I will just need the hot water only setting for a bath or a shower.

Bit annoying the way it has been left but I am worried if I get someone else in to try and get it working as it should, it might end up worse again.

The only thing I wonder about is why there is only four terminals compatible with the three port valves five wires that seems really odd.