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Evohome Worcester Bosch Settings Help

Posted: Mon Jan 23, 2023 9:39 pm
by Mark8par
Hi, I have had Evohome installed for a few years, it's been quite solid and never really had any issues.

Anyway, we have switched over to a smart meter recently and I noticed our high gas usage and wanted to check the Honeywell was working as it should, the chap who fit the boiler didnt really know much about it. I know it would have been better to get a connected specialist in to install the boiler and check it over but I have found them difficult to get hold of and not really interested unless they installed the evohome system, the original Evohome installer has gone missing. So I am stuck between a rock and a hard place at the moment and left to try and find out for myself.

I wanted to check the system parameters are set correct but not sure what they all do.

Current settings are,

Internal Sensor ofset - set to 0
Cycle Rate - Set to 6 per hour
Minimum on time 2 mins
Fail Safe Enabled
Hot Water Temp - Set to 60 (on the boiler this is set to 65 I believe)
Hot Water Overun - 0
Hot Water Differential - 10
Hot Water Priority - Enabled

My system is as follows,

Bosch Greenstar 8000 35 Life System boiler - this was recently installed
Hot water cylinder (Sealed)
Evohome system
12 x zones - 11 of them have HR92 installed
The remaining zone being Polypipe wet under heating system with a BDR91 controlling the Polypipe ZRU PB970028, I spoke to Honeywell who said this should be setup as a Zone valve.
1 x Hotwater Kit

I also wondered if opentherm was worthwhile but to be honest I don't know enough about it.

If anyone has setup a similar system I would really appreciate any help or guidance and if you need to know anymore about the system I will try to answer.

Thanks
Mark

Re: Evohome Worcester Bosch Settings Help

Posted: Mon Jan 30, 2023 8:48 am
by Richard
Depends how evohome has been fitted tbh Mark.

TPI settings for a gas boiler is normally 6 cycles per hour and min on time of 1 minute. I don't normally set fail safe mode to be switched on.

Hot Water Priority is only really useful when the evohome has been installed and wired for this. Has your boiler got weather compensation? If not look at getting this as a way of compensating the heating to a more efficient point.