Honeywell CM67

60 discussions on HomeOwnersHub about the Honeywell CM67: what owners asked, what went wrong, and what fixed it.

What owners report

CM67 Optimum Start algorithm

I've just finally bitten the bullet and installed a Honeywell CM67Programmable Room Stat in my hallway. I bought the version with OptimumStart capability - which purports to decide for itself when to switch on theheating in order to achieve...

Mixing header and pumps

My understanding is that most domestic unvented heating systems use theboiler's pump to circulate water and on/off valves to divert water to thehot water cylinder or heating zones.Under what circumstances should the zone valves be replaced...

Which Combi System

Hi all.Many thanks for replies to a previous post of mine.I think a Combi system is the wisest choice for my situation.But as for which set up, I don't know.These seem to be the options... 1-3 suggest a lot more plumbing work.Option 2...

Boiler sizing from heatloss calculations

Hi,I've done the heatloss calculations on my house and came out with afigure of 8.4kW. What factor would I need to multiply this figurewith to get the boiler size? I am assuming that I will need to allow7kW for the DHW.Is there any...

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