Pump/boiler running continuously...

[sistoat]

Right, where do I begin!

Fitting a new kitchen before chrimbo and decided to take the plunge, stretch the finances to get the economy going again (!), and get a new boiler while I was at it (boiler lives in a nice new kitchen cupboard now).

The plumber stated our wiring was a bit funny and 'not normal' to the wife before he left but all seemed to work ok he said.

About a week after the new boiler was fitted we noticed the whole system was running constantly (boiler & Pump on all the time).

Phoned up some drayton stockists (we have a Y Plan system with an HTS3, and RTS1 an LP522 and an MA1 mid position valve) who agreed it was all wired wrong and sent me the correct wiring diagram for our installation. Armed with that I re-wired all in correctly.

Problem still remained.

Tested various things and replaced both stats (hts3 was defo's shot) and the programmer. All was working fine.

About a week later the same issue raised its head again. I have done all the tests (remove orange wire) to check it's not the MA1 and even bought a new head for it and wired it in - still no joy.

Anyone got any ideas?

I noticed last night (re-wiring it all for a second time!) that the MA1 responds to the central heating being turned on and off but there's no response to the hot water being turned off. neither of the thermostats seem to make any difference...

Does anyone have a list of voltages that should be at each terminal in certain conditions. The terminal with grey wire from the MA1 never drops below 80V but I have no idea if that's normal or not.

 

[jackthom]

if you followed the standard diagram with an 8-way connecting strip you probably have the orange wire from the 3-port valve and the call from the cylinder thermostat wired to position 8.

I would start by removing the wire from the other side of 8. Then the boiler/pump should receive no demand signals at all and won't fire up.

If it does carry on running after this there's something amiss in the boiler itself.


If that did stop the boiler running you could try replacing that wire and instead removing the valve orange from connector 8.
Then the boiler should at least halt when the dhw cylinder gets up to temperature, regardless of the room thermostat setting.
If that works as planned finally the cylinder thermostat call could be removed to check that the CH room thermostat can start/stop the boiler.

 

[D_Hailsham]

if you followed the standard diagram with an 8-way connecting strip you probably have the orange wire from the 3-port valve and the common from the cylinder thermostat wired to position 8.

It's the Call from the cylinder stat which should connect to 8. Common goes to programmer HW On and Sat to valve grey.

 

[Agile]

There is a lot of required information missing!

You have not advised the make and model of boiler!

Nor have you said what the pump is connected to!

Virtually all boilers now control the pump.

Later today I am going to a new boiler because the pump is running all the time, but thats probably a PCB fault though.

Tony

 

[jackthom]

Duplicate deleted

 

[jackthom]

It's the Call from the cylinder stat which should connect to 8. Common goes to programmer HW On and Sat to valve grey.

I've a printout of a PDF (Sundial?) for the various plans in front of me which is now going in the bin. Thanks.

 

[sistoat]

Thanks for the quick responses.

Pump and boiler are both connected to and powered up by the control system (using the switched live to power both - fed out from junction 7 on the diagram that is also connected to the MPV orange wire and the call from the HTS3).

Both are working correctly I'm sure but the switched live is always on.

 

[Agile]

There is a lot of required information missing!

You have not advised the make and model of boiler!

Virtually all boilers now control the pump.

Tony

Almost certainly you have it wrongly connected then!

Please read what I said before!

The boiler can only control the pump when the pump is connected to the boiler pump connections.

If you dont want to tell us the boiler model then there is a limit to what we can do to help you!

Tony

 

[jackthom]

You need to isolate the two sources of this switched live in turn, one from the Cylinder thermostat and the other from the orange wire to see which one is staying permanently live.

Also note Tony's posts above.

 

[sistoat]

Thanks for all your comments.

I took the orange wire out of the system this morning and all stayed live so that only leaves the heating stat feed. Obviously I will re-confirm this when I get home but assuming the heating stat is where the permanent live is coming from I wonder if you have any top tips on moving back further.

Obviously re-checking my connections in the stat is first up but as I mentioned earlier the stat is brand new and was working fine but now has no effect.

As for Tony's thoughts - am aware of the boiler running the pump ideally but that's not how it's setup currently and want to make sure this switched live is working correctly first before I get on to sorting that out!

For reference thought the boiler is a Remaha Avanta 18v.

 

[jackthom]

If it's coming from the cylinder stat, double check the connections are OK....


C 'common' , fed from HW ON (timer/programmer)

1 'call' , goes to join the valve orange wire etc.

2 'satisfied', connects to both the valve grey and HW OFF on the programmer.

 

[sistoat]

right. Here's the long and the short after the overnight investigations.

It was indeed the hot water side of things that was staying live BUT - the NEW programmer NEVER turns off the hot water (HW ON is always 240V and HW OFF is always dead - no matter what the programmer says it's doing).

Also the NEW room stat is always sending 240V down the CALL line when powered up (no matter what temp it's set to and despite it 'clicking' as you turn the dial as normal) and the NEW boiler stat is doing the same.

Just to repeat it was all working perfectly after I replaced these components (another reason why I'm convinced it was wired in correctly) and now a week or two later has done this and is exhibiting the same symptoms that led me to replace all that stuff in the first place.

I am convinced it was all wired in correctly according to the diagram the drayton supplier sent me for a Y plan and these pieces of kit.

I can only now think the final switched live is taking too much power and frying things BUT there's no real evidence anywhere of anything getting hot at all and if it's just powering up the pump and boiler how can that be?

Do I actually need to reconfigure the whole system so the switched live is only sending a signal to the boiler to fire and it then runs the pump to reduce the power needed on that line?

Is there anything else it could be?

Thanks in advance for all your help. Much appreciated.

 

[D_Hailsham]

For reference thought the boiler is a Remaha Avanta 18v.

That's probably the most important bit of info you have given! The wiring of a Y plan for this boiler is shown on page 25 of the Wiring Manual.

Make sure both links on X2 are removed.

 

[sistoat]

D_Hailsham - thanks for the link. I have the book of that and it's certainly not how it was wired in by the guy who fitted it.

In fact I know that the links in X2 are still there and the pump and boiler L on X6 is being fed from the switched live in Junction 8 on the remaha diagram, rather than X6(L) being constantly live and using the switched live to feed into X2 (1) instead.

Would this setup draw too much current and cause stats and programmer to break?

I was hoping to get the control side of things sorted before I re-wired the boiler and pump but I guess you are suggesting the 2 are not seperable?

 

[D_Hailsham]

In fact I know that the links in X2 are still there and the pump and boiler L on X6 is being fed from the switched live in Junction 8 on the remaha diagram, rather than X6(L) being constantly live and using the switched live to feed into X2 (1) instead.

1. The boiler needs a permanent supply to X6. (It needs this for pump overrun)
2. The pump must be connected to X4. (if not the overrun will not work)
3. The links should be removed and terminal 8 connected to X2/1

Would this setup draw too much current and cause stats and programmer to break? I was hoping to get the control side of things sorted before I re-wired the boiler and pump but I guess you are suggesting the 2 are not seperable?

I wouldn't have though so. I say you should always follow the manufacturer's wiring instructions. Can you post a diagram showing your existing wiring?