Heatpump Hot on Gas Side But Cold On Wet Side?

[paul_jefferson]

Mitsubishi Ecodan 2011 8.5kw

Hy Guys, I have just installed a second hand ecodan, all seemed to be going well until i noticed that the flow temp doesn't increase much, infact 2 degrees in 40 mins, then the pump shut off with a over temperature warning on the gas side.

I have it piped up to a 300l grant solar cylinder (Indirect).

On first glance I thought it was no circulation but I defiantly have circulation, spent hours making sure.

Inside the ecodan, the gas to the plate exchange pipe gets red hot, the return at the bottom stays cold.

I am using a ftc2. it configured for dhw only at the moment. I have a 5kw ecodan that works perfectly on the same setup.

Any advice would be greatly appreciated.

Thanks in advance

Paul.

 

[ShaunCorbs]

The solar coil doesn’t have enough surface area you need a min of around 3m2 also have you used 28mm piping and a buffer ?

 

[paul_jefferson]

The solar coil doesn’t have enough surface area you need a min of around 3m2 also have you used 28mm piping and a buffer ?

The solar coil doesn’t have enough surface area you need a min of around 3m2 also have you used 28mm piping and a buffer ?

No buffer, I am going to use one eventually but just wanted to test the heat pump as I have 15 days left on my buyer protection. I used 22mm Pipe.

 

[paul_jefferson]

No buffer, I am going to use one eventually but just wanted to test the heat pump as I have 15 days left on my buyer protection. I used 22mm Pipe.

It should show a little heat though right? it goes from 17 to 20 degrees after about 45 mins you can hardly tell from feeling the pipe that there is any kind of heat coming from the heat pump.

 

[ShaunCorbs]

What temp is it set to 35 c ?

 

[paul_jefferson]

What temp is it set to 35 c ?

the ftc2 is set to 50 its programmed for dhw only

 

[paul_jefferson]

the ftc2 is set to 50 its programmed for dhw only

It just kicks the heat pump on if its desired temp is higher than actual temp.

 

[ShaunCorbs]

Roughly how much 22mm do you have ?

 

[paul_jefferson]

Roughly how much 22mm do you have ?

5 meters

 

[paul_jefferson]

5 meters

Roughly how much 22mm do you have ?

Just noticed your in north wales, I'm in denbigh.

 

[ShaunCorbs]

5 meters

Needs to be 28mm and ideally a solar coil bigger / no less than 3m2 surface area should be listed on the data badge

 

[paul_jefferson]

Needs to be 28mm and ideally a solar coil bigger / no less than 3m2 surface area should be listed on the data badge

I am trying to figure out if the heat pump is working or not, it should heat the water up a bit right? after 40 mins the flow temp goes from 17 to 19

 

[ShaunCorbs]

But if the pipework is restricting the heat pump it just won’t heat / only heat up it’s self and cycle a heat pump needs 4 times the amount of flow than a normal boiler does, can you rig it up temp into a container to see if it flows and runs etc ?

 

[paul_jefferson]

But if the pipework is restricting the heat pump it just won’t heat / only heat up it’s self and cycle a heat pump needs 4 times the amount of flow than a normal boiler does, can you rig it up temp into a container to see if it flows and runs etc ?

ok, i see. but the 5kw ecodan I have heats up right away. just the 8.5 that doesn't.