Alpha 280e and Combimax DHW problem

[jimn10]

I still have the problem where the DHW will often start as hot, but a trickle first thing in the morning, then after a short while going to full flow, but after running for a while at all times of the day, will slow to a trickle for about 5 minutes and then go back to full flow.

I have cleaned the inlet filter to the boiler, it's just had a new pump which didn't change much except the full flow lasts a little longer I think.

Looking at the installation guides, it could be the wax capsule on the combimax, but I'm told these are very reliable, or it could be the combimax store thermostat playing up.

Doesanyone out there have experience of a similar fault on these?

Thanks

Jimn10

 

[BOB D.O.L.E]

I think this is something to do with your dhw flow valve on the diverter valve.

 

[jimn10]

Bob

Thanks for this - the DHW pin is operating ok - comes out when there is a demand and when there is full flow the water is hot enough. The CH works ok so I don't think the diverter has gone.

I'm pretty sure the trickle is due to the outlet thermostat on the Combimax shutting off the flow due to the store temperature being too low. When this happens a bypass from the hot water feed into the Combimax can supply limited amounts, and it is hot. Normally I would suspect a blocked secondary HE or filters etc, but the problem first thing is a mystery because even if bits were working at reduced capacity, I would have expected it to heat up overnight (it's not time clocked - always on).

My suspicions are the store thermostat (it's in series with the Combimax pump) and may be cutting out the supply of hot water back into the store, or the overheat thermistor cutting out heat to the primary and thus the DHW for short periods of time.

These Combimax's are just a bit odd and I was hoping someone out there might have come across this fault and know what the problem is.

Jim

 

[grittishbass]

does sound very much like a sticking wax capsule. if i remember rightly located on the front of the storage cylinder/combimax. don't see them very often though