Opimising UFH with a Heatmiser UH8 wiring centre

[Marnhullman]

I have recently moved to a new build house with underfloor heating on the ground floor and radiators on the first floor. The bedroom rads have a timer and there is a separate timer for the towel rails. The UF heating is controlled by individual Heatmiser V2 stats which are connected to a Heatmiser U8 wiring centre.

I want to run the system as efficiently and economically as possible.

The UH8 user guide refers to a UFH/RAD switch but, I cannot find the switch on the outside of the box; I assume this is normally set at installation (currently it must be set to UFH because the ufh is operating) but it occurs to me that it would be a good idea to select RAD during the summer months when heating is not required? Otherwise, I believe it would be necessary to set each room stat at minimum but, hot water would unnecessarily still be fed to the manifold?

One other issue is that the domestic hot water is dangerously hot, the boiler is set to 72°C and the hot water cylinder temp is set to 65°.

I would be grateful for comments re. the above and advice for setting the system for greatest efficiency.

Thanks

 

[dilalio]

What uh8 do you have?
Can you post a link to the user guide where it says this?

Normally, with UH8 and UH8-RF, the UFH/rad switch is an internal relay which allows you to control a radiator circuit separate from the UFH circuit, using a heatmiser neo stat.

It basically means you connect a motorised valve to the UH8 which is activated by a neo to send power to a 2 port MV. This then fires the boiler and CH pump. The UFH pump remains dormant in this instance.

 

[dilalio]

Yes, as said... UFH/RAD switch allows you to use zone 8 as either a radiator circuit or another UFH zone.

 

[Madrab]

the boiler is set to 72°C and the hot water cylinder temp is set to 65

They both need to be dropped.

Both the boiler and the HW stat can be lowered to 60Deg.

That internal rad switch isn't for playing with at any time. As long as the rooms where the stats live are warm enough then they will never call for heat and the UH8 will never fire up the boiler. Only when the HW calls for heat will it fire the boiler and then the cylinder should have it's own primary feeds and shouldn't go anywhere near the manifold.

 

[Deleted member 281264]

What boiler do you have? you might be able to set it up as a hot water priority system

Heatmiser is crap, UFH should be controlled by an electronic mixing valve/actuator

 

[Madrab]

Heatmiser is crap, UFH should be controlled by an electronic mixing valve/actuator

May help if you can actually support that with your mixing valve recommendations and why you believe that a tried and trusted approach is wrong? Why do you say Heatmiser is crap?

 

[Marnhullman]

Thanks to all. I will leave the UH8 well alone!

Just looked in the Glowworm user guide and it says the boiler factory setting is 75°C! I will try turning it down to 60° also the domestic hot water cylinder stat down to 60°.

One other thing: I had to reset the clocks on all of the Heatmiser neoStat V2 room stats for BST but noticed dates and years were all wrong although I reset them before going on holiday. One of the stats now only shows the Power icon and the Hold icon: the Holiday and Edit menu icons are missing. I tried resetting the stat but the device does not respond. Any ideas?

Thanks

 

[Madrab]

Take the batteries out of the bottom and see if it resets. I must admit it is a failing of the Heatmiser stats where it doesn't have auto DST

 

[dilalio]

Take the batteries out of the bottom and see if it resets. I must admit it is a failing of the Heatmiser stats where it doesn't have auto DST

Neostat v2 is 230v wired.
@Marnhullman you could get a neohub which would give you app control over the system. Makes it easier to set times, dates and schedules.

 

[Madrab]

I'm looking at the NeoAir - not the Neostat - DOH!! The fact it isn't a UH8-RF should have slapped me awake. I have the RF controller myself

 

[Marnhullman]

Many thanks again.

I've managed to sort the room stat - there are no batteries but after reading and re-reading the user guide I seem to have sorted the display. What a performance!

Also reduced the temperatures on both the boiler and cylinder stat to 60°.

I've ordered a neohub.

That's all for now..

Regards

 

[dilalio]

I've ordered a neohub.

 

[Deleted member 281264]

May help if you can actually support that with your mixing valve recommendations and why you believe that a tried and trusted approach is wrong? Why do you say Heatmiser is crap?

Heatmiser is generally used for high temperature manifolds, blending hot 70c water from the boiler down at the manifold which is both inefficient and causes uncomfortable room temperatures. I scrapped my heatmiser uhf 4 and manifold blending valve.

A properly designed UFH setup has weather compensation and an electronic mixing valve and actuator. Having your mixing valve and pump at the manifold is outdated technology.

In this setup a 3 way valve is connected to the return pipe of the whole system and blends cool return water back into the underfloor heating system creating it's own loop. Sounds expensive, but this setup requires no thermostats, zone valves, actuators or room thermostats. Check out ESBE they do some great products.

 

[dilalio]

Heatmiser is generally used for high temperature manifolds, blending hot 70c water from the boiler down at the manifold which is both inefficient and causes uncomfortable room temperatures. I scrapped my heatmiser uhf 4 and manifold blending valve.

A properly designed UFH setup has weather compensation and an electronic mixing valve and actuator. Having your mixing valve and pump at the manifold is outdated technology.

In this setup a 3 way valve is connected to the return pipe of the whole system and blends cool return water back into the underfloor heating system creating it's own loop. Sounds expensive, but this setup requires no thermostats, zone valves, actuators or room thermostats. Check out ESBE they do some great products.

Not everyone is in your position.

 

[Deleted member 281264]

Not everyone is in your position.

Setting up a boiler properly pays dividends eventually. The boiler will stay in condensing mode for longer and use less energy

I can run radiators at 36c, ufh at 30c when it's freezing outside. Flow temp on the boiler 42c, only going to 70c when the unvented cylinder calls for heat as a priority