WB heatslave 18/25 oil

[furryneddy]

Hi all - I have the misfortune of having to work on this boiler this week, it has some "issues" which I hope someone will be able to shed some light on. No.1 Circulating pump runs 24/7 regardless of wether there's call for heat or DHW it just runs constantly ? MI say's it should shut down I even disconnected all the stat plugs from the board and it still runs ?? No.2 Diverter valve problem - I checked the actuator/valve off the board & it's ok, have checked the pin on board connector but when the relay clicks in for the CH demand ie turning the stat on the front panel theres no live on the pin to move the valve over ?? and yes I've tried a new pcb ! please help as my brain is turning to mush everything checks out ok stat wise - don't no where to start looking next ....

 

[Boilerman2]

get your electronic thermometer out and check the store temperature it sounds like the store is not reaching the correct temperature - until the store is up to temperature you will not get a feed for CH (in common with any Combi!) it sounds like the store (HW stat is either faulty or the heat is not being transfered from the boiler to the store (air?)
P.S. I assume this is the Greenstar Heatslave?
happy hunting

 

[furryneddy]

get your electronic thermometer out and check the store temperature it sounds like the store is not reaching the correct temperature - until the store is up to temperature you will not get a feed for CH (in common with any Combi!) it sounds like the store (HW stat is either faulty or the heat is not being transfered from the boiler to the store (air?)
P.S. I assume this is the Greenstar Heatslave?
happy hunting

Hi yes it's the greenstar heatslave ! now then there is a lot of noise coming from it when the diverter is pushed manually over gurgling etc but soon settles down (there's no air elsewhere on the system as AAVs have been fitted in all the right places) customer says that the pumps been running like that since install (4 years) and when started up fires up but seems to over heat on the limit stat rather than what it should and then all controls are null during that time till we get a reset - I pulled the stat out to test this theory and it works ok but what I don't get is why this diverter won't operate in the time before we get this over heat problem (which I think will be easy to sort) in comparison or am I missing something ?? PS. the relay on the board clicks in when the CH stat is turned up and a live appears on the Orange pin ??

 

[oilhead]

Is the AAV on the heatstore doing its job? If you have gurgling, there may still be a pocket of air that the sensor is in. This is similar to a problem prevalent on the earlier heatslaves especially where the boiler was at the high point of the system. The store never reaches temperature, and the demand overheats the water jacket, operating the limit stat.

 

[furryneddy]

Is the AAV on the heatstore doing its job? If you have gurgling, there may still be a pocket of air that the sensor is in. This is similar to a problem prevalent on the earlier heatslaves especially where the boiler was at the high point of the system. The store never reaches temperature, and the demand overheats the water jacket, operating the limit stat.

Hi Oilhead, that sounds like you might be bang on there - thank you I'll check next time I go back.. do you know what temp the store should be at by any chance ??

 

[Boilerman2]

Store should be 75 - 85'c
there are manual air vents in various places on the pipework in the boiler
and of course on top of the store is an AAV

 

[furryneddy]

Store should be 75 - 85'c
there are manual air vents in various places on the pipework in the boiler
and of course on top of the store is an AAV

Thank you boilerman for your really helpful replys - one more question though is should the circulator pump run all day/night 24/7 ?

 

[oilhead]

It shouldn't run all the time, but if something is giving a demand on either heating or hot water, including maintaining the heatstore, then the pump will run. I think your problem is with the heatstore thermostat or maybe the pcb controlling the boiler. Without doing the requisite tests, it is not possible to diagnose.

 

[furryneddy]

It shouldn't run all the time, but if something is giving a demand on either heating or hot water, including maintaining the heatstore, then the pump will run. I think your problem is with the heatstore thermostat or maybe the pcb controlling the boiler. Without doing the requisite tests, it is not possible to diagnose.

Hi - I already changed the PCB, the customer says that the pump's been running since installation (4 years) ? I disconnected all the stat plugs from the board out of curiosity and it still runs !

 

[oilhead]

The only other source of power to the pump, assuming the PCB is O.k. is from the flow switch. This seems to be the only component you've not mentioned, and could cause the symptoms you've reported.

 

[furryneddy]

Hi oilhead, funny you should mention that part as my customer says that that part had been fitted 2 weeks prior to me being called, customer said he had an overheat problem and the previous engineers then fitted a new flow switch and diverter valve actuator and a new mesh filter, but this obviously didn't work as eventually the limit stat kicked in and the customer had no idea it had a reset button not that that would have cured all his problems as his EV was knackered as well. What I find hard to believe is that this pumps run from install - it say's in the MI that it should shut down on demand being satisfied ?

 

[oilhead]

Still check the flow switch. It may not be installed correctly and fouling the pipework. Also check the end switch in the actuator is not permanently on.

 

[furryneddy]

Still check the flow switch. It may not be installed correctly and fouling the pipework. Also check the end switch in the actuator is not permanently on.

Hi - have bleed/checked all AAVs/Manual cocks - no air anywhere, checked that flow switch as I didn't install it when I turned it upside down the circulator pump turned off ! yay I thought but then the boiler wouldn't start at all - oh dear. I wasn't sure which way/orientation this switch is meant to be it was obvious that one way caused the pump to run continuous but on turning the other way nothing happens at all ???????????????

 

[oilhead]

Can't recall the flow switch on this model, but think it may be magnetic. The problem is onviously here, take it out completely and look to see if it is installed backwards. Operating it manually should enable you to ascertain the correct orientation.