Water not circulating

[emailalantaylor]

You wouldn't believe this even if you saw it all.
But the short story is that I have just had a powerflush, cleaned the towel rails specially and I have a magnaclean.
I had a new Heat exchanger installed today in my Vaillant Ecotech boiler.

When we go to turn on the boiler, we find the water is not circulating through the system. Of course the pump is working, no fault showing up on boiler- the hot water just isn't going anywhere!

Yes, valves all open on boiler.

Any ideas what to do next?? A real mystery. My plumber who did the flush tells me that there must be a blockage in the primary flow or return. Really? we just flushed that lot out I thought...

Any ideas??

 

[Billy Bob Bob]

change your plumber

 

[Stuthewarrior]

Check the valves are open on the magnaclean they may have been shut to clean the magnet and not reopened.

 

[emailalantaylor]

Done that. A sensible type suggestion. But they are open. Its got to be something as simple as that. The two valves at the bottom of the boiler are open too...

Well you sound right - but this is the first plumber I have dealt with in a long time who seems to know what its about..and I've met a few recently..

 

[Stuthewarrior]

whats the model of boiler valliant ecotech combi ?

 

[emailalantaylor]

Its a ecoTEC plus 637 system boiler.

Thanks for even thinking about this. it has to be something simple but I'vve lookat the obvious things. i just cannot believe its blocked. We did take a cup ful of Sh** from the whole system , but for the 28mm main feed pipe to block is more than i can imagine. It really looks like a valve is closed - but I cannot see where- unless maybe in the boiler..
but surely the Vaillant engineer wouldn't make such a mistake..
Still waiting for plumber to give me a day to call...

 

[stevetheplumber]

could be an airlock is everything vented fully or have you checked any motorised valves although boiler shouldnt light if these were shut unless wiring is in wrong i suspect there must be some circulation ofr the boiler wouldnt stay alight long

 

[Stuthewarrior]

Just reading your email again you had a power flush done and when he left it was ok ? You have then had a heat exchanger fitted and it has stopped working ?
none of the pipes are getting hot comming in or out of the boiler ?
Just thought I would ask

 

[emailalantaylor]

My system is in three zones and in addition it heats the hot water.
At end of day 1 powerflushing (Zone 1 plus towel rails individually) we tested zone 1 and it was fine. better than ever before. As was the hot water.
At end of day 2 we tried testing system , but it did not seem to work. As the replacement heat exchanger was coming next day I was not keen on 'dirtying' the system with contaminant from boiler - so no full test of zone 2&3 was done. water was ok.
Heat exchanger replaced. Vaillant man said he had to turn off boiler rapidly as water is not circulating.

All I know. It cannot be that there was a huge amount of contaminent from boiler after day 2, because we put fine y filter on outflow from boiler and yes, there ws some stuffin therebut not unusually excessive. Certainly nothing like enough to stop water circulating...
Plumber not coming back ubtil end next week. I gues I'll need to leave it till then and we will discover the mystery..
A

 

[Stuthewarrior]

ok keep us posted on the out come

 

[turnpin]

this heat exchanger was it brand new or possibly a recon? maybe if recon not properly descaled ......!! also check if magna flow valves open may be giving impression they are but if quarter turn type may be obstructed if you can turn pump up to see if it may force the water through.... regards turnpin

 

[emailalantaylor]

Heat exchanger was supplied so far as I am aware as a new one. It came direct from Vaillant and was put in by them.

Today my plumber came. He applied a vacuum cleaner type test to the primary flow and return both on the stystem side and the boiler. There was strong suction on the pipes all round and so neither he nor I think there is a blockage. Vaillant said air is not water so that proves nothing.

We refilled and turned on the boiler. Much crackle and popping. But it didn't just heat up and go off , was able to sustain quietly climbing temperature, but still quite a bit of crackle and pop.
Plumber adjusted boiler by pass and things seemed to get a bit better but not right . Water is definitely circulating - whether at full flow or not we don't know.
Plumber proposes to disconnect heating and water system from boiler and re pipe only the hot water side , turn on the boiler and see if that works. That way, with new piping there will be no question of blockage. Vaillant were non comittal that that proves anything .(!) This is quite a bit of work but what else can we do??

We haven't looked to see if the Magnaclean valves are appearing to be turned 'on' but in reality remain closed. is this a possibility? Will check next week when we do the new piping test..

 

[Bernie2]

Problem with most modern boilers, seems to be, that the plate heat exchangers plates are so close together to make them work fast, that they seem to easily block up.

Lets be honest, some of the old heat exchangers seemed to keep going with what seemed like half bricks or liquid cement circulating in them.

But of course they where not as efficient as todays heat exchangers.

Good Fortune

 

[Nas]

Its Airlock

You wouldn't believe this even if you saw it all.
But the short story is that I have just had a powerflush, cleaned the towel rails specially and I have a magnaclean.
I had a new Heat exchanger installed today in my Vaillant Ecotech boiler.

When we go to turn on the boiler, we find the water is not circulating through the system. Of course the pump is working, no fault showing up on boiler- the hot water just isn't going anywhere!

Yes, valves all open on boiler.

Any ideas what to do next?? A real mystery. My plumber who did the flush tells me that there must be a blockage in the primary flow or return. Really? we just flushed that lot out I thought...

Any ideas??

I had Exactley the same problem on my Brother boiler. I Even replaced the PCB on the boiler and it turned out not to be the problem. The problem On his system turned out to Airlock. I then thought the heat exchanger was blocked, luckily i didnt change it. With airlock there will be no Circulation as was the at my brothers. As soon as his heating fired up the pipes going to and from the heat exchanger would get really hot and the temperature thermistor thought the system was hot it would stop the boiler. In my brothers case he had a polish guy fit it for him and the design was terrible how it worked in the first place I was amazed.

Yot need to remove the airlock and get a new plumber.

 

[emailalantaylor]

Re: Its Airlock

Well thank you. I actually have a new plumber to replace the Polish plumber who did the job.
Your mention of air lock is interesting. The plumber says it sounds like air is the problem. We do not believe there is a blockage, but may go to extreme lengths to prove that by re piping.
HOw do you get rid of an airlock. We have drained th system a number of times...
A

 

[Nas]

Re: Its Airlock

Well thank you. I actually have a new plumber to replace the Polish plumber who did the job.
Your mention of air lock is interesting. The plumber says it sounds like air is the problem. We do not believe there is a blockage, but may go to extreme lengths to prove that by re piping.
HOw do you get rid of an airlock. We have drained th system a number of times...
A

Strange you mention a polish plumber. It was a polish plumber who installed the system at my brothers house!!!

I Managed to get rid of the airlock by increasing the height of the water level in the feed tank to the heating then venting air from the top of the boiler.

 

[emailalantaylor]

Re: Its Airlock

Coud be air as you say.
The funny thing is that if I fire the boiler at lower temperatures it seems to run quietly. But if I increase the heat it starts to 'kettle' and make frightening noises.

 

[Nas]

Re: Its Airlock

Coud be air as you say.
The funny thing is that if I fire the boiler at lower temperatures it seems to run quietly. But if I increase the heat it starts to 'kettle' and make frightening noises.

This was the EXACT symptoms I had. There's probably a design fault in the system causing the air lock. In my case raising the water level in the feed tank and venting from the top of the boiler fixed it.

 

[Bernie2]

Take a look at the design of some heat exchangers and it seems obvious why they can airlock.

Its usually a case of releasing nuts here and there, as air usually gets locked if water comes up the flow and return at the same time, trapping the air in between the two lots of water. Its probably why many boilers have an internal auto air bleed valve on the heat exchanger.

 

[REDSAW]

crack of f & r at boiler

 

[ron12345]

Hi there,

I am also getting similar issue with my Vaillant boiler it's Ecoplus 28.

The hot water works fine but i don't have any water in any of the radiators nor i can hear pipes getting warm.

LCD display boiler solid sign on and bar pressure is 2.7.

I am not sure if my plumber has turn of any pipe undeneath the boiler ?

I would appreciate assistance in this regards,

Best