New build heating engineer needs pointing in the right direction.

[Rodney39]

Hi, I have a vaillant ecotec plus boiler (pre 2012 model) that is giving me hot water issues. It points towards a hot water heat exchanger issue or diverter valve, but I have replaced the diverter valve (old one seemed to still operate as it should as well) so it would seem that wasn't the issue as problem still occured after replacement. I have removed the hot water heat exchanger and rinsed out and blown through it and the water that came out seemed pretty clear. I'm wondering what my next step could be bar fitting a new boiler. The system has a magnetic cleaner installed and I'm aware that this model of boiler has a small filter installed in the boiler workings already, could this be the issue? Any advice is welcome (currently have system cleanser sat in the hot water heat exchanger to see if it loosens anything)

 

[ShaunCorbs]

What’s the fault ? No hot water intermittent??

 

[Scott_D]

Any heating going down then flow when I’m HW?
What’s the inlet gas pressure?

 

[Rodney39]

Boiler is firing on hot water, burner coming on to maximum, temp spiking at about 88 degrees then shutting off and starting the cycle again. Heating working absolutely fine.

 

[ShaunCorbs]

I would say plate if you measure the heating flow into and return out you should be getting around 35-40 difference

 

[Rodney39]

Any heating going down then flow when I’m HW?
What’s the inlet gas pressure?

Unable to check gas pressure at valve as I don't have my screwdrivers (gas valve is awkward to access, pointing towards internal boiler casing, so can't use long neck screwdriver) as they're in my flue analyser bag on site, but can check tomorrow
[automerge]1591817080[/automerge]

Unable to check gas pressure at valve as I don't have my screwdrivers (gas valve is awkward to access, pointing towards internal boiler casing, so can't use long neck screwdriver) as they're in my flue analyser bag on site, but can check tomorrow

Also, have run the heating to check operation after changing diverter valve, so all heating pipework hot at the moment
[automerge]1591817226[/automerge]

I would say plate if you measure the heating flow into and return out you should be getting around 35-40 difference

I'll check when I get my testing gear back, did check the heat exchanger when I had it off and it seemed to be clear and have had some mc3+ cleaner in it for a couple of hours just to see if that helped but no change

 

[moonlight]

Does your boiler have the rubber connection hoses inside? Don't squeeze them, they get blocked and the boat filter. Whats your heating like?

 

[Rodney39]

Does your boiler have the rubber connection hoses inside? Don't squeeze them, they get blocked and the boat filter. Whats your heating like?

It does have the rubber connection hose on the flow/return and the heating is running absolutely fine

 

[king of pipes]

Symptoms point towards a plate partial blockage but it could be a diverter issue if the heating is working then it's one or the other ???? Kop

 

[Rodney39]

Symptoms point towards a plate partial blockage but it could be a diverter issue if the heating is working then it's one or the other ???? Kop

I've changed the diverter valve and the original one seemed to still be moving well also, so it wasn't that part. Certainly seems to be pointing towards the plate. Thanks for the response though pal

 

[Harvest Fields]

Isn’t this an open part of the forum? @ShaunCorbs

 

[Rodney39]

Hi guys, back again. Boiler issue hasn't been rectified. I've now changed the hot water plate and the other was pretty clean so don't think it was that, also I recently drained the system, filled it with adey mc3+, isolated all the rads apart from the circulator so that it ran through just that and the boiler, left it for a week and then drained it all off (was nice and clear again) checked the magna clean (again, pretty clean) and refilled with mc1+ but no change, so I'm going against a blockage. I've attached a video to show the burner start up sequence and how short the burner run time is