Combi boiler. Running CH whilst DHW drained.

[Scotty92]

Have a query regarding a morco combi boiler in a mobile home. It's set up with a link on the thermostat connections within the control panel and heat is controlled by Trv's. I'm planning on adding a hive thermostat to give me more control and intend to use the app. My question is, when the DHW is drained over the winter can I still run the CH via the app. We would use the mobile home a few times over the winter and it would be handy if we could turn the heating on via the app a few hours before hand. I would have to leave the boiler on but the hive app thermostat switched to off. Would any damaged be caused to the DHW side by running the heating. Thanks

 

[garygvl]

Have a query regarding a morco combi boiler in a mobile home. It's set up with a link on the thermostat connections within the control panel and heat is controlled by Trv's. I'm planning on adding a hive thermostat to give me more control and intend to use the app. My question is, when the DHW is drained over the winter can I still run the CH via the app. We would use the mobile home a few times over the winter and it would be handy if we could turn the heating on via the app a few hours before hand. I would have to leave the boiler on but the hive app thermostat switched to off. Would any damaged be caused to the DHW side by running the heating. Thanks

which model of morco have you got

 

[Scotty92]

It's a morco gb24 boiler

 

[garygvl]

It's a morco gb24 boiler

No problem. Make sure preheat is turned off, no point having that on if domestic water drained. Tbh wouldn’t leave a boiler in an unoccupied mobile home during winter without leaving it on some sort of frost protection.

 

[Scotty92]

No preheat I think. As for frost protection when the boiler is switched to zero the frost protection kicks in below 6 degrees I think. So I'm assuming when the boiler is left on and held off by the stat the frost protection doesn't work. Probably add some frost protection through the hive stat. Was just worried that running the CH whilst HW drained would cause damage to the HW side. Does these boilers divert to a secondary heat exchanger for the HW? Had a look at a diagram online and I think that's the set up. Maybe that's standard on all combi's.

 

[Chris B.]

Hi, Scotty92,

I found your original post while researching for an answer to the very same question you asked!
I was wondering how you have got on with your situation, as you had some very good replies.
I have the same boiler, a Morco gb24 in my ABI Lodge and also would like to swap out the mechanical timer and install a Hive system to control the system via my iPhone, so I could warm the home up prior to arrival.
Would you spare me some time and reply with your comments?
Thanks!

Chris B.

 

[garygvl]

No preheat I think. As for frost protection when the boiler is switched to zero the frost protection kicks in below 6 degrees I think. So I'm assuming when the boiler is left on and held off by the stat the frost protection doesn't work. Probably add some frost protection through the hive stat. Was just worried that running the CH whilst HW drained would cause damage to the HW side. Does these boilers divert to a secondary heat exchanger for the HW? Had a look at a diagram online and I think that's the set up. Maybe that's standard on all combi's.

Yes thru a secondary heat exchanger which wouldn’t be used as no water in domestic pipework so no flow from any tap to turn it on