Alpha kettling

[DTBPlumbing]

Hi. I've been working on this Alpha cd18r heat only boiler with f&e tank and separate pump on a micro bore system.
They have had real problems with scale and have had a power flush before. The boiler cuts out and red lights on the front appear, and this is preceded by a banging or kettling noise.
I replaced the pump because it had seized up but am wondering whether it's the heat exchanger that's blocked? It's hard to tell and whether I can remove it and clean it or replace it. What if that doesn't solve it. Either way it's a commitment, short of replacing the boiler. could it be anything else? Thanks.

 

[DTBPlumbing]

Also I've given it a mains flush through and put some scale remover in. Although it's difficult to get it circulated cus the boiler cuts out after 5seconds.

 

[Alpha man]

That will be the Heat ex, very common sadly, try a noise reducer 1st, otherwise it needs replacing!

 

[Ermintrude]

Sounds like a it's time to get in a gas safe engineer for a replacment? Or you could disconnect flor and return from boiler and syphon out all the water then fill it with scale remover then after a few hours flush it out with a hosepipe. But sounds like it's been cooked ! So probably going to need a replacement!

 

[chris watkins]

R U sure there is the required water flow around the system ? is there a by-pass (cut one in ?) worth a check before replacing boiler.

 

[AWheating]

Descale the boiler on its own with your power flushing pump and some acid maybe.

 

[IDCHAPPY]

Also I've given it a mains flush through and put some scale remover in. Although it's difficult to get it circulated cus the boiler cuts out after 5seconds.

If you have an old working pump about(always handy to keep when you are stripping out systems) then you could pipe it onto the system to get it circulating the chemicals?

 

[DTBPlumbing]

R U sure there is the required water flow around the system ? is there a by-pass (cut one in ?) worth a check before replacing boiler.

I havent seen a bypass valve. I'm a bit nervous to remove and clean heat exchanger then the same problem. Then it'll be new boiler time. He won't be happy.
I told him to keep trying the boiler to circulate the scale remover but he said nothing happens now just the red lights.

 

[DTBPlumbing]

The water goes in the top of the boiler, through the heat exchanger then straight out the top again. So surely the blockage is in the HE or the 3port/mid position valve.

 

[DTBPlumbing]

Or could it be the temp sensor? Would that be conducive with the kettling though?

 

[chris watkins]

It may just go in & out of the boiler but the pipework must form a circuit & there must be water flow through the boiler at a rate set by the manufacturer to carry away the 18kW's of heat otherwise the temp of the Litre or so in the boiler heat ex will rise rapidly & boiler goes out on overheat.
jest need to make sure you have circulation.

 

[DTBPlumbing]

Yeah I'm just trying to isolate where the blockage is restricting the circulation. HE or mid pos valve.
ill take the HE out and pour acid in and leave for a day and hope that clears it

 

[AWheating]

If you don't want to take the hex out just cut the pipes, wet vac the water out, put in chemicals to sit, attach power flush machine and flush. Then reconnect. If it's easy to remove the hex then remove it.

 

[Roger Welton]

See. It before a couple of times, you may be lucky if you connect up just the boiler to powerflusher and use a descale, you may not!

Regardless is be looking at the rest of the system to see where the sludge is coming from, pumping over maybe

 

[happyflyer]

Never had all this Tosh in the old days, acid in boilers, where will it all end, BTW the water up here don't do all that stuff, nice and soft like my head..:wazzzup:

 

[DTBPlumbing]

See. It before a couple of times, you may be lucky if you connect up just the boiler to powerflusher and use a descale, you may not!

Regardless is be looking at the rest of the system to see where the sludge is coming from, pumping over maybe

How do you mean, pumping over?

 

[Alpha man]

How do you mean, pumping over?

Really!!

 

[DTBPlumbing]

Really!!

As in why would that cause sludge/scale blockages?
the pump is after the ex pipe.