All sorts of woes

[AIGA]

I really need some help here please.

Glowworm 18 hxi boiler with unvented system. 15 rads.

Radiators were only warm and then hot water was no more than tepid.

Plumber replaced pump and advised system required flushing as too much crap in the system.

Came yesterday and used power flusher for a few hours.

Then tried boiler again but it kept shutting down due to temperature getting too high. It seemed the water was not flowing properly.

Drained and flushed system again and tried again - no joy so we were left overnight with no hot water (save immersion) and heating.

Came this morning and changed pump again - no joy so took heat exchanger off and cleaned / flushed. Replaced and still no joy - boiler kept cutting out (thermistor error or no flow).

Put more Fernox equivalent in system and kept trying to get boiler going but with no luck.

Left us with the news that we should leave the boiler going to let the cleaner work its way through the system and hopefully the blockage will loosen and then allow the water to flow.

So far no luck

Water pump is boiling hot as are pipes near it but any further than 3 inches from pump and pipes are lukewarm. Water is hot though (4 yr old and 6 yr old daughters had a bath!!).

No hot water getting to rads although pump sounds to be turning

Boiler makes banging / grinding noise as temperature approaches 80 - then cuts out.

Been advised also, if this doesn't work we'll need new heat exchanger at £300 ish.

2 questions -

Anyone any better ideas?

Should the crap have got into the heat exchanger in the first place or are the pumbers at fault?

ps: Sorry this is so long and if you got to the end without falling asleep....congratulations.

Thanks

 

[gavinda]

the system should have been properly powerflushed BEFORE the boiler went in. once thers **** in the heat exchanger its doomed. sorry but you need a new one.

if the plumbers didnt do it on installation the yes they are at fault. good luck getting them to admit it.

 

[fitz1]

Two other problems that can cause similar effects are the wrong differential between flow and return pipes to and from boiler and has the condense pipe been checked for partial blockage.

 

[hobroydharry]

May sound daft but are you 100% sure your new pump is turning in the correct direction and fully vented and air free? Worth a look before you spend your cash

 

[Deleted member 105431]

I would advise you downrate the boiler tempoarily, fit a spirovent dirt seperator and a line strainer on the return pipe to boiler. check the pump is fitted correctly and on max speed (grundfos pumps are best, might be worth getting a 15/60). Check that any autobypass is correctly adjusted and system is fully vented and balanced. Make sure the pump is wired into the boiler too.

 

[AIGA]

May sound daft but are you 100% sure your new pump is turning in the correct direction and fully vented and air free? Worth a look before you spend your cash

how can I check?

ps. I'm so damned cold, things are well beyond sounding daft!!

 

[gas4you]

Get your 'plumber' to disconnect the boiler from the system and connect the powerflush machine just onto the boiler tails.