Horstmann H37XL driving me nuts

[gorgonzola]

Hello,

I have a Horstmann H37XL (3 channels) which controls my underfloor heating (downstairs), my radiators (upstairs) and my hot water system.

Up until recently, the channel marked HTG1 used to control my underfloor heating and HTG2 would control my rads, HTG3 for hot water.

All of a sudden, I find that HTG1 controls the rads and HTG2 controls the underfloor heating! HTG3 is unchanged. It is as if the first two channels have somehow mysteriously swapped!

Is there anyone out there that can explain this or perhaps advise me how to change them back?

Thanks in advance.

 

[doitall]

Would have to say not possible, they had to be manually swap.

Just re-set the time for the two zones, and keep zone 1 for the rads.

 

[gorgonzola]

Would have to say not possible, they had to be manually swap.

Just re-set the time for the two zones, and keep zone 1 for the rads.

Thats what I thought but I am not mistaken as I had a sticker on the timer switch itself to remind me which channel or "zone" is for underfloor heating and which is for rads. It is very weird!

I have re-set the times as you suggested but just though that there may be some easy explanation as to why this has happened.

 

[Terrywookfit]

Not possible without changing wiring

Term 1 3 5 are separate relays internally.