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EV =Exp vessel
LLH= Low loss header.
LLH= Low loss header.
B
Bodd
Ok sorry.
these are two system boilers so they have thier own Exspansion vessles as well as a extra vessle fitted externally.
thanks alot Merry christmas to you all I'm off out for the night.
I will bring this up again after christmas so any more ideas please let me know.
Bod
these are two system boilers so they have thier own Exspansion vessles as well as a extra vessle fitted externally.
thanks alot Merry christmas to you all I'm off out for the night.
I will bring this up again after christmas so any more ideas please let me know.
Bod
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As its never worked probably due to bad design of layout,unsuitable equipment choice,undersizing at loads more i cant be bothered to write
i'd be inclined to start again with what you've got but be prepared to have to alter the layout round the boilers.
Just by adding a bigger pump wont solve your problem, but will certainly give you more issues with the boilers perception of whats happening, more than likely they'll start to throw s codes at you very quickly without still getting upto temp.
NRV's are fitted to stop reverse circulation through a non firing boiler.
Job would have worked had they fitted open vents rather than system boilers,its the inbuilt pumps that are the sticking point.
would suspect(without doing the calcs) that the required pump should be about 25-60/80 or even a 32.
Theres lots to get your head round when combinig boilers,unfortunately your facing a quick steep learning curve.
Lee
i'd be inclined to start again with what you've got but be prepared to have to alter the layout round the boilers.
Just by adding a bigger pump wont solve your problem, but will certainly give you more issues with the boilers perception of whats happening, more than likely they'll start to throw s codes at you very quickly without still getting upto temp.
NRV's are fitted to stop reverse circulation through a non firing boiler.
Job would have worked had they fitted open vents rather than system boilers,its the inbuilt pumps that are the sticking point.
would suspect(without doing the calcs) that the required pump should be about 25-60/80 or even a 32.
Theres lots to get your head round when combinig boilers,unfortunately your facing a quick steep learning curve.
Lee
I am not sure that I totally agree with you there Lee.
There may well be circulation issues and I dont understand what he means about how the boilers are combined or applied to the system.
My small concern is that these boilers are of different powers but the same hydraulics so very careful settings would be needed to enable them to track correctly. My immediate reaction is that a flow restriction might be needed on the lower power unit.
Different power boilers seem odd and may be a bodge to increase the output power instead of curing the underlying problem.
That would work fine if they are correctly combined with a sequential controller but we have heard nothing about that. I regularly see total bodges wich would never be expected to perform properly.
In many of these cases there is a lot or work needed and customers rarely understand just how bad previous work is and the cost of correcting it.
Tony
There may well be circulation issues and I dont understand what he means about how the boilers are combined or applied to the system.
My small concern is that these boilers are of different powers but the same hydraulics so very careful settings would be needed to enable them to track correctly. My immediate reaction is that a flow restriction might be needed on the lower power unit.
Different power boilers seem odd and may be a bodge to increase the output power instead of curing the underlying problem.
That would work fine if they are correctly combined with a sequential controller but we have heard nothing about that. I regularly see total bodges wich would never be expected to perform properly.
In many of these cases there is a lot or work needed and customers rarely understand just how bad previous work is and the cost of correcting it.
Tony
Different power boilers will make no difference to the design, installing one smaller boiler in a bank is quite common.
Just set set them as lead and lag with a lower start temperature.
I think the OP is out of scope here, and should be looking to pass it on or getting someone in.
Just set set them as lead and lag with a lower start temperature.
I think the OP is out of scope here, and should be looking to pass it on or getting someone in.
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Basic pump sizing would tell you the internal pumps will not suffice if the loaf is in fact 42KW.
For the correct flow rate at a deltaT of 20deg you'd need a 25-55 and that would only just surfice at 4metre head.
Bad layout bad design,as bod says both boilers are connected via flow and return direct to the system.would be fine with OV's
For the correct flow rate at a deltaT of 20deg you'd need a 25-55 and that would only just surfice at 4metre head.
Bad layout bad design,as bod says both boilers are connected via flow and return direct to the system.would be fine with OV's
B
Bodd
doitall";p="1450632 said:
Well you should.
Because it sounds as though its his bodge work.
If I had just forked out 30K for a heating system and it didn't work I would be furious to say the least.
The boilers have internal by-passes fitted pre set at 0.25 bar.
Do the Vaillant system boilers have anti-cycling timers on them?
If so could the low flow, probably due to inadequate pump capacity, be causing the boilers to cycle and the anti-cycling timing mean the boilers aren't actually firing enough, ie only firing for a few minutes every say 20 minutes dependant on the set-up?
.............if you see what I mean.
If so could the low flow, probably due to inadequate pump capacity, be causing the boilers to cycle and the anti-cycling timing mean the boilers aren't actually firing enough, ie only firing for a few minutes every say 20 minutes dependant on the set-up?
.............if you see what I mean.
Would like to say as a non commercial engineer thanks for all the posts. Like Bodd it's great to get so much information on systems that are a little outside the scope of 'domestic' engineers. So thanks to everyone for their posts. Best of luck to you Bodd.
B
Bodd
Norcon
I'm not sticking up for he fella it is his problem I'm sure he has had plenty of sleepless nights, just happy I'm not in his shoes.
I know they have internal bypasses but I do tend to install an additional one.
Bodd
B
Bodd
Thanks Rojaca
Some of this has been above my head, but at least Im more the wiser. I just want to do whats best for my customer.
Happy New Year
Bod
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