How To Maintain A UFH Manifold Flow Meter

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A sticking or dirty flow meter on an underfloor heating manifold can be an absolute nightmare! It can actually affect the flow rate or cause poor performing zones. In today’s video, we'll talk about how to maintain your UFH manifold flow meter and the simplicity of isolating the manifold, cleaning or replacing the flow meter if needed, and then reinstating it back into the system.
Flow meters come in lots of disguises, depending on the age of the system and the cleanliness of the water in the system. To fix this problem, you need to make sure that the dirt and debris trapped in the UFH manifold flow meter are removed, or else it will stop the flow meter on your underfloor heating manifold from operating correctly.
To demonstrate how you can solve issues that you may encounter in your UFH manifold flow meter, I'll work on a 4-port multiplied manifold. Of course, the first thing you'll want to do is to isolate your underfloor heating manifold by turning off the flow and return ports.
Afterwards, you'll have to depressurize the manifold. Only then can you start working on the UFH manifold flow meter that's causing some issues in your underfloor heating manifold or system.
Watch the entire video to see the rest of the steps and the exact details on how you can get your flow meter running smoothly again in no time!
For more videos like this, visit our playlist of instructional MLCP videos here: • How To Videos - Multipipe
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[@mosso85]

Your style of instruction is perfect. No Umming and Aahing, no talking down to your viewers, no sign of 'Ego' Thank you very much.

[@MultipipeLtd]

Thank you very much!

[@michelledevine4043]

Brilliant video, well explained. Thank you Martin 👏

[@MultipipeLtd]

Glad it was helpful!

[@brianmackney1448]

Very helpful, thank you.

[@MultipipeLtd]

Glad you found it helpful. Thanks for the comment :-)

[@jons6125]

Yes helpful

[@martindennehy3030]

My meters won't adjust any more they're seized solid and I'm afraid to put a pliers on them incase they shatter, one loop to one room seems to be gone cold though the pipes are still getting a little warm. Should i just replace them all ? they're cheap enough, and does it matter whether they go on flow or return ??

[@Pigilili]

Hi! Is there any need to refill some wather into the system? Once you depressurized the manifold, how much water went into the bucket?

[@MultipipeLtd]

as you only depressurise the manifold the amount of water is tiny. but yes, you may need the re-pressurise you boiler as well. (and don't forget to vent the air our of the manifold before switching the pump back on).

[@Pigilili]

@@MultipipeLtd Perfect, thanks a lot. Keep up with your videos, I found them super valuable, as many other people I believe!

[@Chris-gt3rs]

should the flow gauge be filled with liquid? in my house the downstairs manifolds flow gauges are all filled with liquid the upstairs ones have none in the little glass tubes, i ask because the pump is running but not heat upstairs.

[@MultipipeLtd]

Any liquid in the gauges should be ignored. This has nothing to do with the level of flow through the circuit. Sometimes the water pushes the air out of the gauge, but this is not a problem. You need to look for a coloured disc that rises or falls in the glass; this is what indicates flow. If this drops down, this typically shows flow. If you have one loop that is not heating, this is usually a failure of the actuator. If all are not heating, this is typically the pump or mixing valve failure. I hope this helps.

[@Bob_too]

Any suggestions for cleaning a flow meter that is sticking ?

[@MultipipeLtd]

if it is sticking because of limescale you could try a descaler solution and soak them in this. but this may affect the o-ring and may need replacing. Normally they don't get stuck much and simply working them when they are out helps.

[@hottubking1229]

Can you just remove the glass section for cleaning? (Of course still depressurizing the system first)

[@MultipipeLtd]

Thats correct (depending on the type of flowmeter). The glass should separate from the body, unscrewing it whilst holding the main body of the flowmeter should undo the glass. but some flowmeters do not allow this so be careful.

[@ivanmolyneux6225]

@@MultipipeLtd hi there your instructions where very good so thanks for that, however my glass section is so dirty i cant actually see where they have been set too, i could probaly make a good guess but if not iam not sure how to balance the system

[@izmirfication]

Hi, I get heat from the supply manifold when I touch the steel manifold also the floor is heating, but I can't see any fall of the red disc in the glass at any time,tiny red discs are always at the top part of the glass indicators, I have 6 circuits attached to the same manifold,none of the gauges show any flow though hot water gets in to the supply manifold and there's heating in the floor.Can this happen due to too much air in the supply manifold ? Thanks so much

[@MultipipeLtd]

Air is normally shows as the red discs jumping in the gauge. I would suggest for this one it is either failure in the controls that lift the actuators. Or, if all flowmeters are not showing flow the pump might of failed on the manifold which means you would have inadequate flow.

[@izmirfication]

@@MultipipeLtd Thanks so much for your interest

[@Siggles]

Hi. I turned off the flow and return valvues, I have electric actuators. Ive depressurised. But there's still water in the flow meter glass - in all 4. Will that not come out when I unscrew the flow meter? Thanks

[@MultipipeLtd]

Always ignore any water that sits in the flow meter this does not affect the system in anyway you should take you reading from the plunger not the water level. (the reason water ends up in the meter is purely because air compresses so pushes water into the glass higher the pressure more water in the glass).

[@cutefunnyanimals5441]

@@MultipipeLtd Thank you. I really love your videos and it gave me the confidence to go ahead. I took the plunge and swapped them out today and it all seems to work. Well, I say that. I have two manifolds and two Heatmiser Wiring centres. The small leak from the flow meter somehow got in to the wiring centre below and blew the fuse, so I have to get that fixed. Hopefully by checking all is dry inside and swapping the 5amp fuse.

[@handresi]

What is that other loop to the left of the manifold pump? Looks like it has its own temp/pressure controller, and goes back to the main return pipe. Is this some sort of auto bypass?

[@MultipipeLtd]

yes, this is normally fitted if the controls provided on the system does not have a pump delay, this is mainly for protection of the secondary manifold pump to ensure it does not pump against all closed loops.

[@handresi]

​@@MultipipeLtd Ok, thanks. I understand why it might be required, but not the detail on how best to set it up. When 1 or more loops are open, you presumably don't want any water to go via the bypass. When all are closed, you want all the water to go via the bypass. How do you achieve that? What control is on that pipe - is it a pressure relief valve? I guess if the pump is pushing against closed loops, pressure goes up, and then that can release it via the bypass. If a loop is open, the water can freely circulate, so the valve will stay closed. I guess you would set the pressure to be that of the maximum pump output. Am I on the right track, or over complicating it? Perhaps it isn't based on pressure at all, but you always allow a trickle to go back that way? I'll ensure my system has a pump delay, but keen to understand in full what setup you have there. Thank you.

[@torreslondon7541]

I have moved into a house where the UFH manifold appears to have been installed the wrong way around: flow meters on return and TRVs (with thermostat actuators) on flow (hot water in). The system works, but the flow meters always show zero. I assume to make the system work at its full efficiency the manifold needs to be planned the right way round (the reverse of what mine is)?

[@MultipipeLtd]

I would suggest getting a UFH specialist to look at this. Each manufacturer does have different components, and some have the meter designed on the return. Your UFH specialist will check which way your flow should run. However, this normally causes issues with balancing, but the system still should run.

[@torreslondon7541]

@@MultipipeLtd thank you for your reply. The system does run. However, and as you mention, I am not able to control the flow in each room via flow meters and therfore balance the system effectively. Does reversing the manifold arms (or perhaps each valve individually) require draining the whole system?

[@Bob_too]

There are two types of Manifolds from Multipipe/Unipipe/Unicore. I thought mine were plumbed the wrong way around, but looking through the old catalogues I found my version which works with Flow Meters in the Returns. Within the Flow Meters, the springs are at the top and push down the plunger rather than the way all other flow meters work.

[@brianmackney1448]

How do you know when a flow meter is not working?

[@MultipipeLtd]

normally when the pump is running and the actuator is open you should see a registered flow. Sometime the glass can fog up and can be hard to see, but it is worth checking the temperature of the pipe and you should find the flow is warm and the return after 15mins1/2 hour is warm as well.

[@brianmackney1448]

@@MultipipeLtd Thanks for your assistance, the pipe is still cold when the others are hot,I have swopped over actuators and still not getting hot,do you think it's the flow meter as the spring stays at the top.

[@MultipipeLtd]

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[@ttttrant01]

Hello! Is there an optimum flow rate to set the valves to please?

[@MultipipeLtd]

@@ttttrant01 yes, it all comes down to the flow and return temperature you require the output required and the length of the loop. Your UFH supplier should be able to provide you with the flow rates for your specific system. If your system is a Multipipe system then call us or send us an email and we will send this out. .

[@d055e]

Hi I’ve got a customer who’s system I fitted about 7 years ago, going to Chem clean and flush etc for maintaining, on ufh zones I’m going to clean sight glasses etc, could u advise on the use of biocide treating please, does this just get ran through for a period and drained out to treat or left in as addition to inhibitor, t.i.a

[@MultipipeLtd]

@d055e We would always recommend VDI2035 over chemical treatment as this mean less chemical in the water system and continual treatment. But, if you use inhibitors, then a biocide is recommended, and this runs in the system continually..

[@MultipipeLtd]

@@ttttrant01 Apologies for the slow response. the flowrate is dictated by the desired output, length of the loop and system delta T. this calcs is normally done Free of charge by the UFH supplier/ manufacturer.