Complex Leak in system after Heat Pump Install

objectsinmotion

Hi,

I thought I would look here to get some information, as I seem to be going round in circles with Octopus.  Last December I had a Daikin heat pump installed through Octopus, it was a painful process to get that far but I was excited when it went in.  Since then though it's really not been smooth sailing.  I noticed almost straight away that I was having to keep an eye on the pressure in the system as it would drop over the course of a couple of weeks down from 1.2bar.  So much so that I just have the feeder cable attached so I can top it up, although its been off all over the Summer.

The previous boiler based system had no problems at all, I had never topped the water up, I had occasionally bleed the radiators but it was not very often at all and it ran fine.  I have been in a lot of conversation with Octopus who have been out fixed a number of problems I did have, such as parts of the system not bumped in right.  But they have not found any reason for the pressure to go down and say it must be a leak in the pipework.  The house is not old from 1994, and I then spoke to a company who detect leaks who say losing a bar of pressure over 2 weeks will be really hard to find.  However I want to do this in conjunction with Octopus just in case no one finds anything.

I have just spoken to one of the Octopus team today as well who has said I could cause the system problems by toping it up with the mains water, as there will be no chemicals in the system to prevent corrosion.  He also said about tapping off the upstairs to try and show its a problem on the bottom floor.

Has anyone else had issues like this, any recommendations because it's hugely frustrating.  Digging up the floor of the house is not something that makes me happy, expensive to repair and make right afterwards.  Will topping the system up cause problems in the long run, any companies anyone recommends at all?

Thanks

Netexporter

Did they use existing pipework and/or radiators?

objectsinmotion

They replaced a number of radiators downstairs, but used the piping come up and out of the floor on the ones that had been in place already, they touched nothing under the floor..  Also replaced a number upstairs as well.

Netexporter

It's most likely one of the radiator unions. First go round an feel the joints for moisture. If they are all dry then it is probably air ingress on the return leg. If you bleed the radiators, in turn, the one with the most air in is probably the culprit. Tighten the unions on the offending radiator and that will hopefully cure it.

benson1980

I'm presuming you swapped from gravity fed/vented? If so you wouldn't really notice a small leak as the system will just keep topping itself up from the header tank. All you would notice is the requirement to bleed the rads occasionally. It's when you move over to a sealed, unvented setup that you'd notice the pressure drop as top up is manual from the filling loop.

In fairness to octopus it does sound like you has/have a pre-existing small leak in your system somewhere. We had the same thing which we solved by using leak sealer. Lots will slate it for whatever reason but it does work in some cases. We also had exactly the same advice you have had from a leak detection company.

Nick_Dr1

Ours had a small leak with similar symptoms. There was a leak from the isolating tap/valve that connects the outside unit to the inside. Difficult to spot in winter as the ground was always wet but more obvious in summer!

objectsinmotion

I can’t find anywhere that says if leak repair is good in a heat pump based system or bad? Is there any difference in feeding it into the system can it cause any damage.  Hopefully it would work because the leak must be small as it’s a bar around 2 weeks that is lost. 

I have had Octopus out, who could find nothing on the joints and connections including the pump outside. We put little bags on the pipes on the pump but nothing collared in there.