Vaillant ecomax 622/22e

[uniquewater]

Hi, My customer has a vaillant ecomax 622/2e boiler. Since doing a powerflush 2 weeks ago the boiler has recently been making knocking noises and not heating radiators.
the pressure is 1.2, no air in the system or pump. When boiler is first started it fires up heating up to 65 /70 degrees then starts to modulate down until not burning at all. Flow pipe about 1 metre away from boiler gets hot return stays cold. could this be a pump issue? The boiler is not showing any fault codes. Someone had mentioned the black flexi hose can cause problems. I'm going to strip it down Monday but wondered if it was something simple that I have missed. Help / ideas would be much appreciated.

Cheers

Lee
gsr 555497

 

[Ermintrude]

You need to join the gas safe bit for advise on appliances. Message one if the mods

 

[Linkyplumb]

As above, join the gas safe private forum for gas talk.
If return is staying cold then more likely a blockage somewhere than pump, imho.
Had this many times and didnt get any fault codes showing.

 

[chris watkins]

Did you power flush through the boiler ?

 

[IDCHAPPY]

Defo a circulation issue

 

[uniquewater]

Did you power flush through the boiler ?

Yeah flushed through boiler. The strange thing is that I had
heat all around the system a lot quicker than it was before
hand. Customer was saying the radiators were performing a lot better rather than the cold spots.
I will strip down pump tomorrow and check for any blockages.

thanks

 

[Ermintrude]

Flushing through boiler ! DOH!

 

[uniquewater]

Flushing through boiler ! DOH!

I have flushed so many systems through the boilers as this is where half the trouble lies never had this issue before. First vaillant 622 though! Isolated the boiler valves underneath when changing a part on the same boiler , ended up replacing the valves due to them leaking! Got a feeling I'll be changing the temp sensors then although the boiler isn't faulting! Will find out tomorrow and let you all know.
I always cover myself in the estimates so the customer is prepared for something like this.
I had one the other month, 30 year old micro bore open vented with original boiler. The pipes were so thick the actual bore of the 22mm pipework was 5mm. There was bad circulation problems 1 rad out of 10 was ok and that was a towel rail. I got the system working a treat after 2 days of flushing, flushed through boiler, no problems. 4 days later boiler wouldn't fire up, thermocouple had gone!! How can this be related to a flush.? ! Plumbing is a head scratcher always learning!

 

[chris watkins]

Why flushing through them is not such a good idea !

 

[Ermintrude]

Thermocouple probably cooked ages ago, as boiler sludged up heat reflected at tc, when clean heat getting away so tc cools? Never flush modern hex....unless it's just the hex u flushing .

 

[uniquewater]

Just thought I'd let you know how I got on with the vaillant 622/2e circulatio/ rapid increase in temperature. It was in fact the expansion vessel. The charge was zero and when pumped up using foot pump the air was coming out of auto air vent on pump.i removed from system, and just to double check started pumping again and air was coming through inlet of expansion vessel. Split diaphragm. Replaced vessel.
Removed pump head to ensure no blockages, all clear water very clean.
Recharged system bleed air through top part of heat exchanger via test nipple to ensure no air trapped above pump. Turned boiler on. Boiler stayed at a constant temp of 55 flow and return pipes warmed up nicely. Heat everywhere again.
Put boiler in P1 mode to ensure correct temp diff across flow and return. I was getting 18 degrees so was happy with that.
thanks for posts guys on this one , I'm sure I'll be back.