Pump constantly running - no boiler demand

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Hi,

The pump on my system has recently started to keep running 24/7, regardless if there is any demand for CH or DHW.

Pump = Grundfos UPS2 15-50/60
MV = 2 x Honeywell Model ?
Boiler = Vaillant ecoTEC plus 428

Searching on the forum, suggests the MVs could be faulty - however, the pump is wired directly to the boiler itself - the MVs go to a Vaillant VR 65 Wiring Center - with a Vaillant VR 360F Wireless thermostat.



So I am not convinced that one of the two Honeywell MVs are at fault? (They have the little bump on the casing, so can be replaced without draining down - so that is one option I guess!)

Any ideas? Thanks in advance :(
 
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Sounds like the boiler is doing something it shouldn't. you need to get the wiring and the boiler checked by either an electrician or a suitably qualified gas safe engineer. The boiler gives the pump a 2 minute pump overrun and it could be faulty PCB.
 
The Valves control the Boiler only, the Pump is controlled by the Boiler, therefore it follows that the fault lies within the boiler possible PCB fault? ;)
 
If your system is wired as a standard S plan then you could check that both the orange wires from the MV's are 0 volts (when system off) and thus proving the valve end switches are OK.
 
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Thanks all for the speedy responses.

@ 45yearsagasman - yes, this is an S-plan, so great - I will use a multimeter to check the output of the orange wires from the MVs (which are not connected in the wiring center, neither is the grey) to at least put them out of the equation.

Should it be a PCB, I assume this comes with hefty price tag :?:

[I should also add, that the pump was newly fitted by AA insurance and it worked fine for some weeks, before developing this issue]
 
Just in case it turns out to be the PCB - I recon this is the correct Vaillant Part Number for a ecoTEC Plus 428?

0020036861

As a side note, would this be covered under insurance? Just realised I could save a pretty penny like that! :)

Thanks for all the advice :)
 
Just in case it turns out to be the PCB - I recon this is the correct Vaillant Part Number for a ecoTEC Plus 428?

0020036861

Thanks for all the advice :)

If the 428 uses the same part as the 418 (and I think it does) then that is the correct part.

EDIT: Just had a look at the catalogue and that is indeed the right unit.
 
Sounds like the boiler is doing something it shouldn't. you need to get the wiring and the boiler checked by either an electrician or a suitably qualified gas safe engineer. The boiler gives the pump a 2 minute pump overrun and it could be faulty PCB.

A spark !! Give me a break. If you carn't wire up a heating system your in the wrong trade Pete.
 
Just in case it turns out to be the PCB - I recon this is the correct Vaillant Part Number for a ecoTEC Plus 428?

0020036861

Thanks for all the advice :)

If the 428 uses the same part as the 418 (and I think it does) then that is the correct part.

EDIT: Just had a look at the catalogue and that is indeed the right unit.

Appreciate you looking that up mate - cheers :cool:
 
Thanks all for the speedy responses.

@ 45yearsagasman - yes, this is an S-plan, so great - I will use a multimeter to check the output of the orange wires from the MVs (which are not connected in the wiring center, neither is the grey) to at least put them out of the equation.

Should it be a PCB, I assume this comes with hefty price tag :?:

[I should also add, that the pump was newly fitted by AA insurance and it worked fine for some weeks, before developing this issue]

Hello Cabinman, we’d like to address this with you, if you have any outstanding queries, please email the details including your full name, address and policy number to [email protected] with Reference FOR40991. Regards, the Official Representative of The AA.
 
Thanks all, PCB was replaced - pump now behaving as expected / back in control of the boiler.

:cool:
 
Hi,

The pump on my system has recently started to keep running 24/7, regardless if there is any demand for CH or DHW.

Pump = Grundfos UPS2 15-50/60
MV = 2 x Honeywell Model ?
Boiler = Vaillant ecoTEC plus 428

Searching on the forum, suggests the MVs could be faulty - however, the pump is wired directly to the boiler itself - the MVs go to a Vaillant VR 65 Wiring Center - with a Vaillant VR 360F Wireless thermostat.

I think you will find that it is the Grundfos pump you have had fitted. Their new energy saver pumps have a surge problem and have been welding open or closed the relays of boilers or wiring centres. It has become so bad that they are sending out their new OEM pumps with surge protection cables fitted. They will send you one if you ask. If it is not fitted the problem will be likely to reoccur. As it is a manufacturing fault Grundfoss should be asked to pay for the damaged it's faulty pump has caused.



So I am not convinced that one of the two Honeywell MVs are at fault? (They have the little bump on the casing, so can be replaced without draining down - so that is one option I guess!)

Any ideas? Thanks in advance :(
 
TheAA1";p="2755689 said:
Thanks all for the speedy responses.

@ 45yearsagasman - yes, this is an S-plan, so great - I will use a multimeter to check the output of the orange wires from the MVs (which are not connected in the wiring center, neither is the grey) to at least put them out of the equation.

Should it be a PCB, I assume this comes with hefty price tag :?:

[I should also add, that the pump was newly fitted by AA insurance and it worked fine for some weeks, before developing this issue]

Hello Cabinman, we’d like to address this with you, if you have any outstanding queries, please email the details including your full name, address and policy number to [email protected] with Reference FOR40991. Regards, the Official Representative of The :rolleyes:
 

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