Central heating pump running constantly and boiler misfiring

[DIYNOVICE13]

Wondering if anyone can help as I've had a few people come round now with no luck in solving the issue.

I recently moved into my house, as first time buyers. The house is about 12 years old and has a Logic Ideal 12 boiler, which I presume is as old as the house. It runs on a 2 zone system for heating, thermostat in living room for downstairs and hallway for upstairs. With a seperate water programmer under the boiler. This is supplemented by a separately run solar panel system in the summer.

The issue I have is that the central heating pump on the water cylinder is constantly running, even with no demand from heating or hot water. During the summer, this was OK as I turned it off and also the boiler and allowed the solar panels to heat water and this worked fine.

However now it's winter, I need to have the CH pump back on but even with no demand it constantly runs. I've had a zone valve replaced and can see this working when I create demand on the ch system. I had a plumber review the system and he felt it may be due to a faulty thermostat. I've now replaced the water programmer and 2 thermostats with a tado system and I am still having the same issue.

If I turn the pump off, the boiler still fires and if I turn the boiler off the pump still runs.

Every person who comes to review suggests another professional review. But no one has been sure how to fix.

Any advice would be appreciated.

 

[cross thread]

A decent gas engineer or electrician should soon be able to sort it out when they are at the property.

 

[fixitflav]

Wondering if anyone can help as I've had a few people come round now with no luck in solving the issue.

What is the system, do you have a 3-port motorised valve (Y-plan) or two 2-ports (S-plan) (or something else)? If it's S-plan each valve has a microswitch which closes when the valve is fully open, to power the pump and boiler. Switch contacts stuck together would make the pump run continuously, I'd start by looking there.
If that's not it, a competent heating man should be able to suss it.

 

[DIYNOVICE13]

I'm not entirely sure but I would hazard a guess at Y plan
I have a central heating pump with 3 speeds on it, as a dial on the front and then 3 zone valves, 2 for central heating and one for hot water

 

[fixitflav]

I'm not entirely sure but I would hazard a guess at Y plan
I have a central heating pump with 3 speeds on it, as a dial on the front and then 3 zone valves, 2 for central heating and one for hot water

Do you mean 2-port motorised zone valves? If so it sounds like S-plan.

 

[dilalio]

I've now replaced the water programmer and 2 thermostats with a tado system and I am still having the same issue.

And who did the wiring for that?

 

[DIYNOVICE13]

And who did the wiring for that?

I did that.
The wall thermostat was a direct replacement with 2 wire set up.
The water programmer then switched with tado wireless receiver with a custom set up provided by tado. But like I say, I had the exact same issue before too

 

[Harry Bloomfield]

Is the pump, fed by the boiler, so it can run on, after the demand is satisfied - or is the pump fed from the valves, so as soon as the demand stops, the pump stops?

 

[DIYNOVICE13]

Is the pump, fed by the boiler, so it can run on, after the demand is satisfied - or is the pump fed from the valves, so as soon as the demand stops, the pump stops?

The boiler currently thinks there is demand all the time. It remains in C even when heating and water off. But if turn the boiler off on the front switch it will go to 0 but the pump still runs.

I have checked all the valves and each will open on correct demand from each zone. But the pump will run regardless.

I'm just getting increasingly fed up as I can hear the boiler constantly going overnight as it's below the bedroom.

 

[DIYNOVICE13]

Do you mean 2-port motorised zone valves? If so it sounds like S-plan.

Apologies yes. It would be an s plan then

 

[dilalio]

If boiler AND pump running on the it's a MCV issue as microswitch is remaining depressed.

Or... A wiring issue.

 

[DIYNOVICE13]

Thanks.
Ive been trying to find an electrician to come look at it but with limited luck

 

[DP]

Thanks.
Ive been trying to find an electrician to come look at it but with limited luck

It is a heating engineer who you need, one who knows how to fit a boiler, service it as well as carry out repairs. A fitter who only knows how to instal a combi will be out of depth here
I strongly suspect, like Dilalio mentioned, one or both your motorised valves could be defective. Check for 240 volts on the orange wire if you competent to do so safely.

 

[Stuckinarut]

Apologies yes. It would be an s plan then

No need for apologies, you mentioned in your first post you have zonal heating. Sounds like your getting a stray or permanent voltage from somewhere. Has this always been an issue?