Heatslave 20/25 problems

[sdaonline]

Hi, we have a Heatslave 20/25 installed, it had a service last Dec and ran fine for the three or four months after that we used it for. We recently started using it again and all of the radiators apart from one which was stone cold were heating up to maximum even though the boiler was set to the lowest setting. Eventually it has calmed down the the radiators now heat normally but still there is the upstairs one which is totally dead. All rads are full up with water. Also there is no hot water at all coming through the taps. The boiler itself seems to making all the usual noises it used to.

Any ideas on what is going on?

Thanks

 

[Burnerman]

The boiler contains a diverter valve that channels hot water either to its Heatslave tank or around the radiator system as required. If the rads are being used, once hot water is required the valve shuts that circuit off and channels heat to the domestic water.
So, if there's no hot water, there's a diverter fault, more than likely - and often enough its the stepper motor on top of the valve thats failed.
One thing, can you hear a click from the boiler when you turn a hot tap on? This is a flow switch, that instructs the burner to fire when there is demand.
John

 

[triplexxx]

Sounds like a diverter valve as usual, not switching to give you hot water, if the radiator is at top of house above boiler it might struggle to get there,balancing your rads would be an idea ,Search balancing rads. Boiler is discontinued so may be time to invest in a decent one.

 

[triplexxx]

The boiler contains a diverter valve that channels hot water either to its Heatslave tank

Where would that be located? The Heatslave tank?

 

[Burnerman]

It sits just on top of the circulating pump, front of the boiler midships......not too bad to get to!
John

 

[sdaonline]

Hi, the boiler clicks and blasts into life with we put a hot tap on, but nothing comes out, sometimes it may be lukewarm or warm for a bit then it runs out.

Thanks for replies

 

[Burnerman]

Yep, that s the diverter.....the hot water produced by the boiler is going straight into the radiators, instead of the Heatslave tank.
John

 

[sdaonline]

ok thanks for your help, seems to be the culprit - you wouldn't have rough idea of the cost of a repair would you?

Thanks Stu

 

[Burnerman]

That has to depend on the exact fault, Stu.....on top of the brass diverter valve there's an aluminium box, called the power head. The original one will be a Honeywell, but replacements are available for around £40 from Toolstation, and two screws hold them in place.
However, replacement stepper motors are around £15, which requires the power head to be opened up and rebuilt.
Either way, the multiple wire connections (6 I think) go to the programmer PCB at the boiler top.....that's easily accessible with the boiler top lifted off.
To someone familiar, I would say 1 1/2 hours to replace, easily.
However, anyone attending would want to make their own diagnosis, and that's just mine!
John