Manufactures instructions will state gas supply should be of adequate size to supply 20 mbr at inlet.
Insuffcient inlet supply will void any guarantees on a new appliance.
On existing supplys if the gas pressure drop between the meter and inlet at the appliance is more than 1mbr, providing...
Sounds like you gotta leak somewhere.
Check exterior safety relief valve,small copper pipe outside for signs of water.
Check system for visual leaks.Also pay attention to pressure gauge.
Should be 1bar system cold,1.5 system hot.
Could be pressure vessel fault.
I am sure that d70 is for internal divertor valves only will make no difference to external valves.
If you have connected the cylinder stat to +and- this is for ebus only and will not work.This is for the ntc.
3 and 4 should be linked.
Be carefull with second level diagonostics,there are...
Fit mainly Valliants.Good after sales.Good product.
As for sizing modern condensers should be sized smaller and worked harder.
Boiler should be sized as per Part L.Non condensing like the Potterton profile should only be fitted if the installation can be exempted from building regs.
Flow is definately on the left.Its not to say it wont work if the pipes are crossed.Been to many older type boilers working fine with pipes crossed.Modern boilers will not work at all as the temperature sensors are dedicated flow and return.
Would agree that the wiring needs to be checked.All Valliant timers are Hot water priority to stop the weather compensator interfering with the recovery time of the cylinder.With your set up not sure how the boiler will know your demanding for hot water.Check e-bus is wired to boiler and not the...
These boilers work the same as the Utimate Range.First thing i would check is the pilot assembly.Take the injector out and clean.Can leave in vinegar for a while,usually works.Be carefull on removal pilot tubes likely to snap.Then your stuffed.If this dont work could be pcb.Would change...