Got a neighbour with one of these who's having a few issues. 7-8 years old, never been serviced. Prv was passing on it and it was rattling I was told. Sure enough prv was passing and the pump sounded like a bearing was shot. Looking at it, needing a prv, pump and a burner gasket for servicing I said he'd be better getting a fixed price repair from Vaillant, however he thinks he's doing me a favour giving me the business!! Another problem he was having was the hot water running hot and cold, when i first went for a look the burner would go on full, modulate down then back to full and so on. Also when it was manually put to full burner it ramped it to temp then the burner went off. I put this down to the faulty pump.
New pump and prv fitted, heat exchanger/burner/probes etc cleaned and new gasket fitted. Ran the purge mode and fired the boiler, same problem seems to be happening at the boiler to me, my neighbour seems to think its better. On HW the burner goes on max until about 80* then on to low burner til about 70*, this continues. Stick it on full burner for testing and it cuts out again. On heating it just ran high then mid/low until temp was reached.
FGA readings were fine when the boiler was running, however couldn't really test on max as it wouldn't stay on full burner long enough, but no alarming reading when it was running high/low. Inlets ok.
Im thinking a blockage somewhere in the boiler, although the pump and housing weren't really dirty when i took them out, the prv had some grit in it but nothing major.
Anything common problems on these? Or is it worth stripping it down to check for a blockage, this model still has the old rubber hoses on the flow and return, probably should or recommended changing them (and the pressure sensor) but thought it was already costing enough!!
Diverter is a little noisier than normal but seems to be working
New pump and prv fitted, heat exchanger/burner/probes etc cleaned and new gasket fitted. Ran the purge mode and fired the boiler, same problem seems to be happening at the boiler to me, my neighbour seems to think its better. On HW the burner goes on max until about 80* then on to low burner til about 70*, this continues. Stick it on full burner for testing and it cuts out again. On heating it just ran high then mid/low until temp was reached.
FGA readings were fine when the boiler was running, however couldn't really test on max as it wouldn't stay on full burner long enough, but no alarming reading when it was running high/low. Inlets ok.
Im thinking a blockage somewhere in the boiler, although the pump and housing weren't really dirty when i took them out, the prv had some grit in it but nothing major.
Anything common problems on these? Or is it worth stripping it down to check for a blockage, this model still has the old rubber hoses on the flow and return, probably should or recommended changing them (and the pressure sensor) but thought it was already costing enough!!
Diverter is a little noisier than normal but seems to be working
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