UFH Upstairs temperature help

[richo106]

Hi All

 

I have UFH upstairs and downstairs, downstairs in a concrete slab and upstairs in aluminium spreader plates below 22mm T&G floorboards. I have an ASHP with 100L buffer. I have been running the ASHP hot water and heating in line with the octopus cosy tariff (ticks over 24/7 apart from the 3 hour expensive period)

The GF seems to be working well and the floor warms up nicely and all the rooms easily reach the temperature but the upstairs rooms are struggling to keep up and often feel cold especially the bathrooms (cold floor and toilet seat!)

 

usually the temperature in is the same temp out on the u/s manifold which is worrying as it shows hardly any (if any) heat transfer is happening

 

I wish I installed the low profile screed system but it’s too late now obviously and I also put 100mm insulation between floors which is better for sound but not for heating

 

i currently run the ASHP on the weather compensation curve which seems to work ok for downstairs (I have set a upper limit of 23.5 which is hits quite regularly so knocks it off)

 

I had upstairs set at 20.5 but just upped these to 23.5 to see if it makes a difference but not convinced it will at all!

 

what other options is there to try? Could I alter the weather comp curve but that would just click the downstairs off more but suppose the water temp would be higher upstairs?

 

through the day rooms the upstairs temp stay ok due to doors being opened but when the kids go to bed about 7 and their doors are shut it cools down.

 

Will electric towel rails make much of a difference in the bathrooms at all?

 

any ideas/suggestions on what to try greatly appreciated! Electric heaters is my last resort.

 

[richo106]

Just to add I have a pretty air tight house and well insulated house. I also have MVHR

[MikeSharp01]

I suspect we need a bit form information / knowledge to help reliably:

Is it all coming from 1 manifold or more than 1 (how many)?

Do you have multiple pumps in the system or just one?

What is controlling the flows is it individual loop actuators or some other?

 

 

[richo106]

1 hour ago, MikeSharp01 said:

I suspect we need a bit form information / knowledge to help reliably:

Is it all coming from 1 manifold or more than 1 (how many)?

Do you have multiple pumps in the system or just one?

What is controlling the flows is it individual loop actuators or some other?

 

 

Hi Mike

 

There is 2 manifolds, one upstairs and one downstairs.

There is just 1 pump that is common to both (see attached)

Yes all loops have individual loop actuators

 

My gut feeling is there is not enough UFH pipework to make a difference temperature as the person who did my heat calcs said upstairs heating wasn't required, I just put some pipes in anyway on the screw from below type plates (average of 200 centres...see attached pic)

 

Anything that i could do to help would be amazing but at the minute not holding much hope out

 

Many Thanks

[MikeSharp01]

Your pic shows a rather poor connection between the pipes and the floor above, at least in the bits we can see - air is a reasonable insulator so as things stand you are not getting the heat from the pipe into the floor very well, can you still access it or are you beyond that stage already?

 

Going forward there are perhaps two approaches.

1. Try to stop all flow in the downstairs and then experiment with the upstairs manifold flow rates and the water temperature  (+delta T) to see if the upstairs system can be adjusted to cope without the downstairs in circuit. (Keep notes of the present settings so you can return to them at any point.) If it can't then you may need to fall back on making the downstairs do all the work.
2. Do the heat calcs - how much heat you need out of each zone for the length & diameter of pipe, coupling losses, area of the zone etc. Then adjust the flow rate settings in the controller for each zone and see what happens.

I get the sense from your original post that the bathroom is your principle concern so maybe just run / play with that loop. Get a gun type thermometer to measure the temperatures everywhere (pipes, floors etc).

 

[ProDave]

You mention it "clicks off" at 23 degrees.  Is this a room thermostat if so where, and is there a separate one upstairs and downstairs?

[JohnMo]

If you have a mismatch in floor output the simple first step is to reduce output from downstairs and/or increase upstairs.

 

If downstairs gets too hot decrease output, by knocking off 0.5L/min off each room loop that gets too hot. Get downstairs to have a stable temperature before messing with upstairs. You may need to revisit this a few times over a few days.

 

Then increase output from upstairs, go to manifold increase each loop flow by 0.5L/min.

 

Leave for 24 to 48hrs between adjustments to see what happens. You need to ensure any thermostats are set to not influence anything while you set things up.

[Nickfromwales]

9 minutes ago, ProDave said:

You mention it "clicks off" at 23 degrees.  Is this a room thermostat if so where, and is there a separate one upstairs and downstairs?

Sounds like a GF stat, so no separate stat for the FF, so this isn’t sympathetic at all to the two very different types of emitters.

[richo106]

39 minutes ago, MikeSharp01 said:

Your pic shows a rather poor connection between the pipes and the floor above, at least in the bits we can see - air is a reasonable insulator so as things stand you are not getting the heat from the pipe into the floor very well, can you still access it or are you beyond that stage already?

 

Going forward there are perhaps two approaches.

1. Try to stop all flow in the downstairs and then experiment with the upstairs manifold flow rates and the water temperature  (+delta T) to see if the upstairs system can be adjusted to cope without the downstairs in circuit. (Keep notes of the present settings so you can return to them at any point.) If it can't then you may need to fall back on making the downstairs do all the work.
2. Do the heat calcs - how much heat you need out of each zone for the length & diameter of pipe, coupling losses, area of the zone etc. Then adjust the flow rate settings in the controller for each zone and see what happens.

I get the sense from your original post that the bathroom is your principle concern so maybe just run / play with that loop. Get a gun type thermometer to measure the temperatures everywhere (pipes, floors etc).

 

That was the only picture i had of the pipes i could find, the pipes are securely fixed in metal spreader like the pic attached (just an example of how mine is) and yes way passed the stage of accessing them unfortunately

 

I have tired to unscrew the flow controllers on the manifold and it didnt seem to make much difference ( i even unscrewed it too far and it came off...much to the amusement of the wife while water was spurting out!) I have attached the picture of the manifold with the current flow rates

 

[richo106]

12 minutes ago, ProDave said:

You mention it "clicks off" at 23 degrees.  Is this a room thermostat if so where, and is there a separate one upstairs and downstairs?

Yes thermostat, i have a thermostat for each room (so 11 in total) 

 

[richo106]

[Nickfromwales]

1 minute ago, JohnMo said:

If you have a mismatch in floor output the simple first step is to reduce output from downstairs and/or increase upstairs.

 

If downstairs gets too hot decrease output, by knocking off 0.5L/min off each room loop that gets too hot. Get downstairs to have a stable temperature before messing with upstairs. You may need to revisit this a few times over a few days.

 

Then increase output from upstairs, go to manifold increase each loop flow by 0.5L/min.

 

Leave for 24 to 48hrs between adjustments to see what happens. You need to ensure any thermostats are set to not influence anything while you set things up.

Best approach at this exact moment, to see if what you have can be rescued.

 

If the FF heating cannot get those rooms to 21°, without the help from the GF UFH, then it’s just not been installed well, eg with very little contact between the plates and the 22mm deck. I always staple the life out of these plates to have as much surface > surface contact as is possible, normally using an air powered or electric stapler.

 

If there’s not much contact then the plates would need a big uplift in flow temp to compensate.

 

Ive done installations with “J” plates, and they can work well, but not if the heat can’t transfer to the deck. 

[Nickfromwales]

5 minutes ago, richo106 said:

Oh lord. 
 

This is NOT a great way to install UFH….

 

They should have notched the tops of the joists, not dropped down and under! These are now all significant air traps, and as the water flows so very slowly any trapped air cannot escape by being pushed through by the pump. 
 

Did you witness the installer purging every single run one by one, with cold mains pressure to evacuate the air and ensure each loop was completely populated with water?

 

This needs to have been done religiously. 

[ProDave]

5 minutes ago, richo106 said:

Yes thermostat, i have a thermostat for each room (so 11 in total) 

 

Then it should all work.

 

Are you SURE it has been wired properly so when all downstairs rooms are up to temperature and the downstairs UFH controller is off, does the upstairs UFH continue to run and most important does the ASHP continue to run?

 

Agreed some balancing needs doing, but apart from different rates of heating at the moment it should work.

[richo106]

5 minutes ago, JohnMo said:

If you have a mismatch in floor output the simple first step is to reduce output from downstairs and/or increase upstairs.

 

If downstairs gets too hot decrease output, by knocking off 0.5L/min off each room loop that gets too hot. Get downstairs to have a stable temperature before messing with upstairs. You may need to revisit this a few times over a few days.

 

Then increase output from upstairs, go to manifold increase each loop flow by 0.5L/min.

 

Leave for 24 to 48hrs between adjustments to see what happens. You need to ensure any thermostats are set to not influence anything while you set things up.

Hi John

 

These seems interesting i will try this, by decreasing the flow downstairs will that automatically send more heat upstairs (apologies for the very daft question)

 

I wanted to run it constantly off the weather compensation curve but the GF was getting too hot so put a limiting temp in the thermostats (23.5). I didn't want to knock the weather comp temp down as in my head it would only decrease the temp upstairs further

 

[richo106]

6 minutes ago, Nickfromwales said:

Best approach at this exact moment, to see if what you have can be rescued.

 

If the FF heating cannot get those rooms to 21°, without the help from the GF UFH, then it’s just not been installed well, eg with very little contact between the plates and the 22mm deck. I always staple the life out of these plates to have as much surface > surface contact as is possible, normally using an air powered or electric stapler.

 

If there’s not much contact then the plates would need a big uplift in flow temp to compensate.

 

Ive done installations with “J” plates, and they can work well, but not if the heat can’t transfer to the deck. 

I installed the plates, i used lots of small screws with large heads so contact with the surface is not a too big of concern for me (at the minute)

[Nickfromwales]

1 minute ago, richo106 said:

Hi John

 

These seems interesting i will try this, by decreasing the flow downstairs will that automatically send more heat upstairs (apologies for the very daft question)

 

I wanted to run it constantly off the weather compensation curve but the GF was getting too hot so put a limiting temp in the thermostats (23.5). I didn't want to knock the weather comp temp down as in my head it would only decrease the temp upstairs further

 

I’d firstly shut the GF UFH off by closing all the loops and see what happens to the FF. 

 

Best to just pull the band aid off and start there imho. 

[Nickfromwales]

3 minutes ago, richo106 said:

I installed the plates, i used lots of small screws with large heads so contact with the surface is not a too big of concern for me (at the minute)

16mm pipes? 

[richo106]

5 minutes ago, Nickfromwales said:

Oh lord. 
 

This is NOT a great way to install UFH….

 

They should have notched the tops of the joists, not dropped down and under! These are now all significant air traps, and as the water flows so very slowly any trapped air cannot escape by being pushed through by the pump. 
 

Did you witness the installer purging every single run one by one, with cold mains pressure to evacuate the air and ensure each loop was completely populated with water?

 

This needs to have been done religiously. 

This is not my install BTW, i have posi joists. Which were lots of fun threading all the pipe through!

 

Installed the pipes but the guy setting it up filled them with water...he did say they filled up nice and easily with water

 

Is this something i can do now just to ensure its ok?

 

[richo106]

2 minutes ago, Nickfromwales said:

16mm pipes? 

yes 16mm Thermrite

[richo106]

4 minutes ago, Nickfromwales said:

I’d firstly shut the GF UFH off by closing all the loops and see what happens to the FF. 

 

Best to just pull the band aid off and start there imho. 

I will do, in an ideal scenario what will having to FF?

 

My concern is the delta T temps are the same so no heat transfer

[richo106]

10 minutes ago, Nickfromwales said:

I’d firstly shut the GF UFH off by closing all the loops and see what happens to the FF. 

 

Best to just pull the band aid off and start there imho. 

Could i do this by turn the thermostats off?

[ProDave]

2 minutes ago, richo106 said:

Could i do this by turn the thermostats off?

Turn ALL GF thermostats down.  That should shut off all downstairs loops.  And will also test my question, does the upstairs manifold continue to work and does the ASHP continue to work.

[Nickfromwales]

2 minutes ago, richo106 said:

Could i do this by turn the thermostats off?

Yup, as long as there are actuators per loop that will close off flow. 
 

8 minutes ago, richo106 said:

I will do, in an ideal scenario what will having to FF?

 

My concern is the delta T temps are the same so no heat transfer

What this will do, is give 100% pump potential to the FF manifold, which is what we need for a practical test run.

 

Defo needs a FLIR / IR thermometer so you can see the heat pushing through the pipes (or not). 
 

13 minutes ago, richo106 said:

Installed the pipes but the guy setting it up filled them with water...he did say they filled up nice and easily with water

Sorry, that doesn’t answer my question. The loops need to be purged one by one with cold mains. If this didn’t happen then it needs to, if you’re looking to eliminate every possible reason why this isn’t working properly.

 

My immediate gut feeling is that you should defo have had 2x manifolds, each with their own pumps, and each with a TMV; this would allow a higher flow temp to the FF UFH and for the GF to be dialled back accordingly. 
 

You have 2 very different emitters here, BUT, if well insulated/airtight/MVHR then the requisite heat for the FF should be minimal.

 

17 minutes ago, richo106 said:

This is not my install BTW, i have posi joists. Which were lots of fun threading all the pipe through!

I’m glad, as the install in the pic is 🐕 💩. 

[Nickfromwales]

10 minutes ago, richo106 said:

Could i do this by turn the thermostats off?

There still needs to be a call for heat obvs. 
 

This may require you to turn them all to max and manually close each loop off via the flow gauges.