Boiler + Pump staying on

[PhilGP]

I have a 'Glow-worm SPACE SAVER 52' boiler which stays on after the CH/HW signals have stopped. I do not have any wiring dagrams for this boiler.

This fault only occured a few days ago and I originally assumed it was the old programmer stuck on (Danfoss 3060) but I have now replaced it with a Sunvic 207XL and the fault remains. If I remove the programmer and switch on the power, I still have power at the boiler Live and pump Live (i.e. the HW signal from the programmer)
Its almost like the boiler is sending out a live to drive the pump.

any ideas?

 

[chrishutt]

Micro switch on a motorised valve sticking on. Check what motorised valves you have, usually just after the pump.

 

[PhilGP]

The valve is a Honeywell V4043 (H1007).

I have posted details of the plumbing on a previus thread and I think it's a very old design.
The pipe from the boiler goes to the pump which then goes to a 'T' junction (going up+down). Up goes direct to the hot water cylinder (no stat), Down goes to this valve and then onto the radiators.

How can I check the microswitch ?

 

[chrishutt]

You need to study the circuit diagram for a 3 port mid position valve and check that everything is doing what it should at each stage. There are two inputs - a white wire which is live when the heating is ON (timer and room stat) and a grey wire that is live when the hot water is OFF (timer or cylinder stat).

If those inputs are as they should be, then the output (orange wire) to boiler and pump should be live only when they are required to be on. If the orange is live when it shouldn't be then the valve head (actuator) will need replacing, which might involve replacing the whole valve.

 

[PhilGP]

I dont think my wiring or plumbing is 'standard' ...

The programmer has been replaced but even with it disconnected, the HW signal is still live!

The valve is a two-way which just controls the CH. There is no cylinder thermostat.

 

[chrishutt]

Sorry, I didn't read your previous reply properly. It's obviously not a 3 port valve but a 2 port. In which case the orange output wire should be live only if the brown input wire is live and the motorised valve has opened.

On second thoughts, that doesn't fit with the circuit diagram. The live for the boiler and pump doesn't appear to be fed from the motorised valve as would be normal.

Starting a new thread on this problem isn't a very good idea because we can't see what has already been discussed and resolved. Better to continue the existing thread.

 

[PhilGP]

it hasn't been resolved this is a new problem

 

[chrishutt]

Is the system wired up in accordance with the circuit diagram above? If so, are you getting a live from the programmer hot water on? If not, how can the boiler possibly be coming on? The pump might come on if the pump overrun switch is suck on, but the boiler shouldn't fire.

 

[PhilGP]

To the best of my knowlegde, this is the current wiring - although I'm not convinced it is correct.
With the programmer disconnected from the system completely, there is a live on the HW signal. I can only assume it's coming out of the boiler - which again seems very odd.

How can I find out about the pump over switch - the pump is a Grundfox 15-50 with just three wires (L/N/E) attached?

 

[bengasman]

Old control system using different brands and not certain that is has ever been wired up correctly in the first place.
Your best chance, if you insist on diy, is to buy a control pack, take all the old carp out and replace it with new components of one brand that are designed to work together. If you get the Honeywell, you can suffice replacing the heads which will safe you a messy job.
Bear in mind that you are working with 230V, near water and very low resistance conductors, unless you are competent with electrics, I would strongly recommend getting a pro to do the job.

 

[chrishutt]

To the best of my knowlegde, this is the current wiring

To the best of your knowledge? Are you a lawyer? We need straight answers - yes, no or I don't know will suffice.

 

[PhilGP]

Ok, I've done some more checking.
I have elliminated the programmer, and pump (by removing their connections).
The switched-live supply to the boiler is not connected to anything yet it is still live.

Is it possible that the permanent live and switched-libe inside the boiler have shorted out (or a component failed) ?

I have removed these cables from the junction box and tested then with a continuity tester and they are connected - A lot of wires are hidden behind walls and under floors so I cannot confirm they go directly to the boiler.

 

[chrishutt]

Is it possible that the permanent live and switched-libe inside the boiler have shorted out (or a component failed) ?

Yes. If you have a permanent live and a switched live to the boiler it is probably because there is a pump overrun switch, which may have stuck on. You should also check that live and neutral are not reversed on the main supply. What happens to the boiler switched live if you disconnect the permanent live?

Are you sure you're boiler is a Space Saver 52? I can only find references to 50s, which don't have a pump overrun or a permanent live to the boiler. Can you quote the Gas council No - e.g. 41.313.03?

 

[PhilGP]

Does anyone know where I can get wiring diagrams for a 'Glow-Worm Space Saver'?
The diagrams inside the boiler cover are so old I cant read any of it.

 

[PhilGP]

You should also check that live and neutral are not reversed on the main supply.

We had a rewire about 3 months ago without any boiler issues since - I will check it anyway.

What happens to the boiler switched live if you disconnect the permanent live?

I removed the permanent live from the junction box (not boiler).
The switched live behaved itself - i.e. only came on when HW was called for.

Are you sure you're boiler is a Space Saver 52? I can only find references to 50s, which don't have a pump overrun or a permanent live to the boiler. Can you quote the Gas council No - e.g. 41.313.03?

It's definately a 52
The number is 41.315.45