Atmos boiler flow temp problems!

[Agile]

An ex-BBC colleague recently emailed me to ask about a problem he has had with an Atmos boiler recently installed for him.

Has anyone else had this problem and if so what was the solution?


This is what he said to me:-


Hello Tony,

Just thought I would let you know how I got on with the Atmos - mainly because it's been a bit of a saga.

The installation went OK and looks a tidy job but the boiler cuts out and resets itself regularly and as a result doesn't warm up the house very well.

The boiler water temperature was only getting up to 60 degrees regardless of what it was set to. They spoke to Atmos and changed some settings and it now gets up to about 68 degrees max. but its still not enough for the house.

They say that it's a design problem and does this on larger installations. However, the installer (Atmos approved) tried running it with just the hot water (Santon 250) and the symptoms were just the same. Atmos say they will supply a modified control board but can't say when - the software will need changing apparently.

What do you make of all of this and have you come across it before ? They say that there are 3 or 4 larger installations suffering from this problem.

 

[Dan Robinson]

The pump is too small and the boiler is registering too high a delta. Come on Tony - surely you could have diagnosed this easily enough .

I assume of course you have checked the the thermisters?


The pump in the standard InterSystem HE26 is 4metres IIRC.

 

[simond]

Dont see how this can be a pump/system size issue. The problem persists with just the cylinder connected.

 

[Agile]

I have not been there and its not my job! Its also in Tring !

In any case the approved installers are on the job and discussing the problem with Atmos who seem to agree there is a problem. Since the installlers seem to be aware of other installations with the same problem its apparently somewhat common and I thought someone here would be aware of it.

If we dont get some further suggestions I am going to have to suggest that he uses the electronics fiddle of adding resistance in series with the sensors to fool the boiler.

As you say Simon as it gives the same problem on the low resistance cylinder coil as well it does not sound like a Δ T problem.

Any more suggestions?

Tony

 

[Dan Robinson]

Well the only time I have hit this problem it has been an under sized pump.

I cover Tring, if they get stuck, send them my details.

Remember I have the software and lead to interrogate the boilers sensors AND calculated values.

 

[mehran]

If it was me...I would fit a second pump or replace the internal one.

As Dan said atmos has under sized the pump but you can easily wire in a second pump just under the boiler using the same teminals as the first.

 

[gaswizzard]

What's going on with these manufactures? , 4m head circulators , 10 litre EVs , shocking state of affairs. , be better off leaving the pump/EV sizing to the installer and trimming some off the cost of these boilers.

 

[Dan Robinson]

Dont see how this can be a pump/system size issue. The problem persists with just the cylinder connected.

Possibly throttled back to the short and curlies

Not saying there isnt a boiler issue, but.....

 

[Dan Robinson]

What's going on with these manufactures? , 4m head circulators , 10 litre EVs , shocking state of affairs.

Cost cutting and SEDBUK. they offer a 6m upgrade for larger outputs after feedback from installers. Atmos will listen and do what they can. At least they don't presume installer error off the bat.

 

[gaswizzard]

Dan , I'm not reffering to Atmos but all manufactures , they seem to design the boilers with no margin for error regards pipework sizing , they want it both ways , they size the circulators based on low velocity #s (larger pipework) and in turn supply an EV that would just about be large enough for a rabbit hutch.

 

[gaswizzard]

they offer a 6m upgrade for larger outputs after .

Then they need to look into correct system design.

 

[mehran]

Dan, do you think a 4m pump should ever of been in a 26kW system boiler? The risk of the boiler been trapped in a low power output state be apparent?

 

[ecowarrior]

Dan / Mehran - I fitted a 30/36 today & tried to get into some sort of Engineers mode to see if I could tweek the CH o/p up to 35 Kw with the fan speed - how do u get into it? do u have to have the laptop & software (Come back Ferroli - all is forgiven!) Oh _ I didnt need 35Kw for this job but looking ahead to this twin boiler affair I am hoping to do soon. IG told me to sort the Cascade software I would need the laptop? - Recon it will be a stat on the return pipe then

 

[mehran]

to save
a long post I will video me doing it on my own boiler...

 

[Dan Robinson]

Kim, seend me a text - I'll be up for a bit. Or go to the CC

GW, I totally Agree, in Atmos' case it has some part in the SEDBUK rules and the fact they are hobbled out of the box.

They realized the dumbness of it and provided the bigger pump option after I ( and not wanting all the credit) and a few others highlighted the folly.