New UFH wrong side of pump ?

[skeltonmfc]

Hi Guys

Im after any advice or if someone can recommend a good heating engineer in Thanet ?. I had a Wundafloor manifold installed for our groundfloor and new extension (currently 4 zones running) and im having problems with the whole system now and the plumber is ghosting my calls.

The current setup is a 28mm flow & Return pipe from the boiler (Utility room) (Baxi Solo 30 HE) runs up to the unvented cylinder in the loft room in which they have teed off in the utility room just after the boiler with 22mm flow and return pipes that connect into the manifold (checked and these are the correct way around) which is located under the boiler. we also have rads on the second floor in every room and still a few rads downstairs in the rooms we haven't refurbed yet but these seem fine. I have bled all the Rads of any air.

By the Unvented cylinder there are 2 x 2 port valves 1 on the primary flow into the unvented cylinder and 1 on the heating circuit for the rads behind the cylinder their is quite a big Pump (Grundfos) these have always been there as had the unvented cylinder so the only new piece is the manifold

The UFH has auto-balancing actuators and is controlled from a Heatmiser wiring center, when the heatmisers thermostats call for heat the wiring center activates the Boiler switch Live and UFH pump starts (Grundfos set to 3 as advised when i spoke to the manufacturer)

Since they installed i have had the following problems:

1. a couple of times a day boiler gets a fan error (i replaced the fan still the same error)
2. Hot water isn't getting as hot as it used to it's getting around 34-35 degrees (i know from my boys bath temperature gauge)
3. Return pipes on the manifold isn't getting hot
4. Flow gauges only drop to 1/2 l/min even if i remove the actuator and open fully

have they connected the flow wrong, should the 22mm Flow to the UFH be after the pump in the loft ?

Any advise would be appreciated

David

 

[ShaunCorbs]

Have they installed a pump to pump to the manifold since they teed off before the existing pump ?

 

[skeltonmfc]

Have they installed a pump to pump to the manifold since they teed off before the existing pump ?

Hi Shaun

The only other pump is the one that came with the manifold

 

[ShaunCorbs]

There’s your problem as this is designed just for the manifold not to get water to the manifold so it’s incorrect installed / piped up

 

[skeltonmfc]

Thanks for your help, i thought it looked wrong, could i get an additional pump before the manifold or can you only have one circulation pump

 

[skeltonmfc]

I managed to rectify this myself today, I ran 22mm pipe up to the loft pump and put my flow on the other side of the pump, my boiler problems have stopped 😊I also fitted a 2 port valve on the flow to the manifold that the heatmiser controls and thought that was sorted but now I’m having other issues

Bathroom circuit on the manifold is working fine (smallest circuit) flow gauge drops and return gets hot after a few mintues

Kitchen dining circuits x 3 all three only really go to 2 l/min I have fully opened the gages and tried removing the actuators still no luck

Also there is a mixer valve on the manifold that I have set to 45 degree and it stays this temperature all the time the rads in the rest of the house are calling for heat, as soon as the rads go off it spikes to 65/70 degree ?

 

[ShaunCorbs]

Has he or you flushed the loops out of air ?
What spikes the temp going out through the manifold ?

 

[skeltonmfc]

Yeah I re-pressurised with a hose and purge out any air.

On the other side of the flow pump on the manifold there is a temperature gauge this is what spikes it’s like the mixing valve isn’t regulating the temp of the water coming into the manifold.

When I ran the new flow to the other side of the pump in the loft I didn’t change the return this still goes into the boiler return into the untilty could this cause a problem because the flow and return are about 10m apart?

 

[ShaunCorbs]

Might need to purge more out of the individual loops

It’s plumbed into the mixer correctly eg flow to flow return into return ?

 

[skeltonmfc]

Yeah flow into red mark on the mixer return into blue.

I ran through the individual circuits one by one with the hose no bubbles come out in the bucket then moved onto the next one, when I was doing this the flow gauges dropped right down as expected but as soon as it’s running of the system no flow again, it’s strange as bathroom works fine as expected bathroom is the last circuit on the manifold

 

[ShaunCorbs]

Try screwing the flow meters in might be all on max / fully open

 

[Locoblade]

Yeah I re-pressurised with a hose and purge out any air.

On the other side of the flow pump on the manifold there is a temperature gauge this is what spikes it’s like the mixing valve isn’t regulating the temp of the water coming into the manifold.

When I ran the new flow to the other side of the pump in the loft I didn’t change the return this still goes into the boiler return into the untilty could this cause a problem because the flow and return are about 10m apart?

Interesting, I've also got a Wunda manifold with their Salus auto balancing actuators and I'm also seeing unusual temperature spikes at the manifold that I'm trying to rectify.

I installed a cheap Wifi thermostat to tuck into the manifold inlet temperature probe pocket replacing the little gauge so I could see a graph of what it was doing through the day and what's happening with mine is from cold when a UFH zone first calls for heat I get an initial spike in manifold inlet temperature to about 55-60c for maybe a minute, despite the blend valve being set to 35c. After a minute or so the temperature reduces but how far it drops is dependant on what/how many zones are calling for heat. If there's only one small zone running the inlet temperature refuses to drop below about 50c. If another zone comes on the temperature in the manifold drops to around 40c (it never actually gets as low as 35c even when all zones are open), but shut it back down to one small zone and it goes back up to around 50c. So, everything seems to point towards the blend valve bleeding in too much hot water for the amount of flow around the loops.

I went through this with Wunda support and they sent me a replacement blend valve but fitting that hasn't improved things. If I dribble hot water through the flow side of the spare valve manually you can see it closing up as it gets warmer because water starts exiting out of a different hole so it seems to be functioning to a degree albeit not under pressure. Also if I turn the blend valve on the manifold from 35c to say 40c the manifold temps also climb about 5c so it is doing something with the incoming water.

The last correspondence I had with Wunda they were suggesting it's likely a heating design issue talking about the bypass circuit not doing it's job but I don't buy that (I don't think the bypass should need to do it's job if the system was working correctly) and given their tech tried to tell me the blend valve was basically just a tap you open more or less to allow more hot water in with no thermostatic element reacting to temperature I kinda lost faith at that point but my feeling is there's an issue with the way their valve works being overwhelmed by the incoming flow/pressure and is opening when it shouldn't do.