Heating but no hotwater, and yes I have searched the forum!

metis1419 · 11 Sep 2007

I know this must be a common problem but I searched the forum and could not find someone with the same issues!

I have recently moved into a new house and the hot water has not worked since moving in, it will only work if I put the immersion heater on, the CH works fine.

I had a little investigation today and it seems the boiler is not switching on when I select hot water, it only on switches on if I select heating.

Does this pretty much point to a faulty heating control/programmer unit as it seems it is not telling the boiler to give me hot water?

My boiler is an: Ideal E type RS ballanced flue gas boiler.
The programmer is the old Landis & GYR dial type.

Thanks in advance for any help!

namsag · 11 Sep 2007

Probably a Faulty motorised valve/ or cylinder stat

ChrisR · 11 Sep 2007

A lot of those timers are going wrong about now. Needs a voltmeter to diagnose.

How many motorised valves do you have and what type?

metis1419 · 11 Sep 2007

I checked the thermostat on the cylinder - it was set too low for the boiler to come on, the boiler now switches on fine so it's not the timer.

There is a valve next to the hot water tank that has recently been replaced, I can hear this opening and closing but it does not seem to pass any hot water through - the pipe is very hot underneath but the pipe going into the cylinder stays cold.

Could the new valve be faulty too or could it possibly be something else?

SWOLLENGLAND · 11 Sep 2007

The fact that you can here the motor in the actuator turning is not conclusive proof its turning the spindle in the valve ,I recently had the same problem but in reverse ,hot water ,no heating found i neede to change the valve body as well as the motorhead or actuator

GeckoGas-com · 11 Sep 2007

Any idea what valve it is; certain valves have a tendency to "fall apart" internally; blocking the flow of water.... Additionally; if you have the heating and hot water on; does the pipe to the hotwater get hot?

Are there any gate valves on the "return" of the cylinder (The pipe usually directly below the one with the valve for the HW) - Is it open?

Symptoms · 11 Sep 2007

If you're confident enough swap the HW & CH cables at the controller that'll determine if its's knackered. My bet is on a zone valve problem; yours might be opening ok to allow water to pass but the micro switch inside isn't being activated. This switch is a critical part of the control setup, controlling the pump, the gas valve, etc. Depending on the type of zone valve you can get replacement motor heads, some are easy to fit without having to drain the system, others not.

metis1419 · 12 Sep 2007

The valve is a honeywell V4043H1056 and is brand new, I have looked the part number up on the internet and it is a 22mm 2 port zone valve 240V.
It was fitted by a plumber just before we moved in as he apparently thought the valve was the problem and had assumed everything was working.

The return pipe has a manual stop valve (the normal red handle type) and yes this is open.

I have tried turning the heating and hotwater on at the same time - the pipe going to the valve gets hot but the pipe from the valve to the hotwater tank still stays cold.

dal5band · 12 Sep 2007

I don't know if this is possible guys - is it possible to take the valve actuator off and try turning the valve stem with a spanner. Oil ?

metis1419 · 12 Sep 2007

What does the manual arm at the bottom of the valve do, is this supposed to manualy open the valve?

I tried moving it but there is no resistance in it and it does not seem to make any difference.

grib · 12 Sep 2007

If there is no resistance on the arm it means the valve is activated and should be open. Yes you can take the actuator off... i'm not sure of the part number you quoted but is it a silver metal box?

If so you take the top off (one tiny screw on the end) and there are two brass coloured screws, one on either side of the actuator which you have to loosen ...TURN OFF the electric to the heating system before you do this. The head should then pull off. To replace it is easier if you first push the manual lever over and hook it in the open position.

Mostly when these valves go wrong (assuming it's the type I'm thinking of) they "let by" ie the water passes through when you don't want it to not visa versa.

It sounds like the valve is working to me so could it just be a circulation problem.... check the ballcock in the expansion tank (if you have open vented system) probably 8 times out of 10 when I get called to a job and heating works but water doesn't it's becuase the ballcock is stuck and tank is empty.... give it a wiggle... let it fill and everything starts to work.

metis1419 · 12 Sep 2007

Expansion tank is full of water and ballcock working, just went up there and checked.

Can I just confirm that if the valve was working properly it should let the hot water pass and go into the hot water tank?

If so then I guess the valve is still faulty and it either was not fitted correctly or was not working from new?

dal5band · 12 Sep 2007

As I suggested, take off the actuator and try moving the spindle on the brass valve. This way you can check
1 That the spindle and hence the valve moves and is not stuck.
2 Determine which way is open and which way is closed and ensure you put he actuator back on the right way.
3 That the actuator is sitting firmly on the brass body and engaging the spindle fully.

The electrics to boiler and valve should be switched off.

Otherwise it's a drain down plumbing job to unblock the problem.

grib · 12 Sep 2007

Yep take the head off and try to turn the valve manually... it's just a rubber ball on an arm inside and should move easily........ but I still have to say I've never known one to be stuck shut, usually the ball swells up (ouch) and gets stuck half way so it won't shut. But maybe it's just a faulty valve. Does sound like it's time for the hose pipe.

One last though (You'll still need the hose pipe) If the expansion is full yu can still have a similar problem if the cold feed is blocked. Seems to happen more when the cold feed is too close to the vent.

metis1419 · 12 Sep 2007

Thank guys, I will try you suggestions on the weekend and let you knwo how I get on!

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Heating but no hotwater, and yes I have searched the forum!

namsag

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