Possible Problem with an EVOSTA 2 pump

[David Woods]

Hi all,

I have had a new Grant boiler system fitted which powers 22 rads and an immersion heater - 8 of these rads are large double convectors. We have had a lot of issues with the install of this Grant boiler but my main issue is if the pump is man enough for this system. As mentioned it's a DAB and my feeling is it's not powerful enough for this setup as the rads never really get very hot - also taking a long time to heat up. The system has been bled many times although not much air comes out. Most of the rads have thermostatically controlled valves.

The installer has got fed up going back to try and resolve a short cycling issue (Grant were hopeless as well!)

We have a large 5 bed detached property and we are burning through tons of oil to warm the place up.

So I was wondering if a kind soul could tell me if this pump is fine for the job or should I look at getting a plumber to upgrade it and what setting should it be on.

Now I realise this is not easy to comment on this remotely and we have had ongoing issues with short cycling with the boiler (Don't Buy a Grant!) - but I wondered if an underpowered or incorrectly setup pump could be causing the lack of heat and short cycling - thinking the water is not being pushed around the system efficiently.

I would be grateful for any comments on this prior to taking then next step.

Also wondered if this make of pump are ok as always had Grundfos in the past.

I am not a plumber but an an electrician but don't intend doing any work on this myself - each to their own trade!
Thanks - Dave

 

[ShaunCorbs]

Open vent or sealed

Size of boiler eg kw

Pipework to the rads 10 or 15mm ?

 

[exedon2]

Do you know what the heat requirement of your radiators actually is? This of cause assumes that heat loss calculations have been done and radiators are correct size.
To be fair to Grant they are reliant on the boiler -pipework- pump ect been correctly specified and installed for there boiler to work correctly.

 

[king of pipes]

Grant to be fair are usually a reliable unit if installed and commissioned correctly, the Dab evosta 2 has 3 different sets of control built in - set on its constant speed 3 it should move the heating water through your system efficiently to a height of 8 m? Try checking all your trv valves fully open ? also check your lockshield valves are open ? is there a automatic bypass fitted to provide a passage for heated water through the boiler when demand is reduced ? Set the pump to a constant speed setting - try speed 2 first then 3 to see if this improves the distribution of heat ? also set different times to heat your hot water from heating your radiators , if this doesn't improve things then your system may need attention . Regards kop

 

[John.g]

The Dab Evost2 is a 7M pump so should be man enough for the job and certainly shouldn't cause rapid cycling of the Grant boiler. Check which of these settings its on or post a photo the setting.