Alpha CD35c NO HOT WATER

[Kev the gas]

My father in law moved in February, Alpha cd35c installed. approx 3 1/2 years old {not under warranty :cuss: }

On the day he moved in I had to fit a new head to the diverter valve on the advice of Alpha tech help line.

Hot water never really worked well since, it now comes on for about 15 seconds and then shuts down, for couple of mins then starts up for 15 secs, water only gets luke warm then stone cold. No heat is dumped down the heating flow or return.

Central heating seems to work fine, any ideas ??

An old gas valve is by the side of the boiler.

Kev.

 

[tweakyboy]

Have you checked resistances on themistors? If not could possibly a blockage in the plate heat exchanger.

PM Alphaman, he is the man for Alphas! :stooge_moe:

 

[SimonJohns]

Sounds to me like dirty plates

 

[dancinplumba]

is pump running

 

[jtsplumbing]

Get the gas pressure checked ! then as other replys, dirty plate heat exchanger or themistors

 

[Kev the gas]

is pump running

Yes pump runs, heating works fine, boiler in loft and circulation to the system is fine.

The whole system was installed when the boiler was fitted, by a couple of BG engineers as a private so we are told, 28mm gas ect so hopefully inhibitors were used !!

 

[Alpha man]

Blocked DHW heat exchanger, or divertor valve motor.

 

[Kev the gas]

I fitted a new motor in Feb, looks like I need to take the heat exchanger out and have a little look.

Just had a quick look approx £150 plus vat, hope it can be cleaned. A t that sort of price i would be tempted to suggest a new boiler.

 

[Kev the gas]

Quick update, I went today to remove heat exchanger, and thought I would double check.

The motor head I fitted in February has stopped working !, 240 v to the motor as reqd.

Manually pushing in the spindle on the diverter valve the boiler was still cutting out after 15 seconds.

The heat exchanger was removed and found to be full of crap on the heating side, 3 1/2 years old new system !!

Cleaned out and refitted again tested manually the hot water is king hot !

Moral of the saga;-

NEW SYSTEMS REQUIRE CHEMICAL CLEANSING AND INHIBITING.

ALPHA DIVERTER HEAD MOTORS LAST 2 1/2 MONTHS.

Kev