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Discuss Wiring Help Needed replacing a Horstmann C27 with Flomasta 7635 in the Central Heating Forum area at PlumbersForums.net

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Hello - I'm a relatively new owner of an old house here in France that was updated by the previous owner who lives in the UK. He used one channel of a two channel Horstmann C27 to control turning on and off the electric water heater. Given that I'm from the states, I'm not all that familiar with this system, but did figure out that the switch controls a 3a solenoid/relay that also had to be replaced after a power surge knocked out this entire timer system.

While online in France, I was able to purchase a Flomasta 7635G which is a single channel switch which also seemed to me is all that I need. However their were no installation instructions and screwfix only has instructions for the the two channel version which looks like how my Horstmann is wired. The only instructions I have are on the schematic on the back of the device which looks a little different than the schematic of the Horstmann and how it is currently connected. Before I do something stupid, I'd like a second opinion.

PS - the water heater is working fine - after testing it and replacing the solenoid/relay, I've been manually turning the breaker on & off while waiting for this new timer to arrive.

You'll note the current Horstmann wiring diagram. To confirm, there are two leads from the 230v mains connected to the Neutral & Load terminals - as I understand it, these control the actual timer. There is also a Neutral wire running from the N terminal to the solenoid/relay followed by a Load wire running from terminal 3 on the block to the solenoid/relay which as I believe would be my 3a output leads for the solenoid/relay.

In looking at the wiring diagram on the back of the Flomasta, I'm unsure if I should leave my Neutral solenoid/relay wire where it is, connected to the N terminal, or move it to the 1 terminal of the wiring block that reflect COM.

Thank you in advance for input.
 

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Live directly to prog via a 3 amp fused spur on L terminal
Neutral directly to prog via 3 amp fused spur on N terminal

3 core flex from prog to relay

terminal 3 on prog to a1 on relay / contractor
Neutral on prog to a2 on relay / contractor
 
I’m confusEd, is it an electric boiler?
Yes - it's a domestic electric hot water heater that's controlled (turned on with) this timer/relay unit. I'm bypassing the timer now using a toggle switch on the relay that is closing the contacts. I want to make sure that when I connect the new timer that it works. The previous owner used a 2 channel system - however there is no need to the 2nd channel, since there isn't a heat pump or secondary device that needs to be turned on at the same time. It's only a timer/switch for the hot water heater to control when it goes on and off to save $$$ on electricity - it only runs during the night when electric rates are low.
 
Live directly to prog via a 3 amp fused spur on L terminal
Neutral directly to prog via 3 amp fused spur on N terminal

3 core flex from prog to relay

terminal 3 on prog to a1 on relay / contractor
Neutral on prog to a2 on relay / contractor
Shaun, Thanks for your help - given my location in France, it's been hard to get parts and test what's good and what's bad. Now that I have all new parts, I'm still not able to control the relay/contractor - and I'm just not sure what's wrong. After getting a second brand new in the box Flomasta timer (the first one received from the UK was used and not disclosed at the time I purchased it...) - and a new relay, I'm not getting ANY voltage reading from the timer when it's on - and - it's not triggering the relay.

I've tried two different connections:
Using a 3 amp fused spur for both: Live/Load directly to prog on L terminal / Neutral directly to N terminal.
1st try / previous install: terminal 3 on prog to a1 on relay/contractor & N terminal on prog to a2 on relay / contractor.
2nd try / showing on back of prog: terminal 3 on prog to a1 on relay & terminal 1 on prog to a2 on relay.

Before connecting to the relay, I'm testing the circuit for voltage and I'm not seeing any. Should I be seeing 230v? I am getting when the prog is in the on mode, but nothing when off, telling me I'm getting a closed circuit.

I'm certain what's happening is that I'm not getting voltage to turn the relay on - the relay / contractor works fine once I flip the override - and - it's a new relay.

Thoughts??? - and thanks again for your help!
Jon
 
Have you linked L to 1? (On timer)
 
Have you linked L to 1? (On timer)
No - so to confirm, what you're suggesting for this third attempt is the following:

Using a 230v / 3 amp fused spur for both: Live/Load directly to prog on L terminal / Neutral directly to N terminal.

A jumper from terminal L (load) on prog to terminal 1 on prog
terminal N (neutral) on prog to a2 on relay / contractor
terminal 3 on prog to a1 on relay / contractor

Now when the timer is on - it will close the circuit / and conduct 230v through the relay / contractor - hence the diagram showing a dotted line between L & 1 terminals??
 
Correct
 
Yes some are linked internally eg Drayton lifestyle are

Some you have to link externally
 

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