how to top up a solar hot water system

Hi,

I have a solar hot water system in my house (came with the house when i bought it)

The pressure in the system is low and i want to top it up. (lower than shown in the attached picture)

the system is filled with a glycol mix, so i would have to top up with that fluid.

but i am wondering is can i use the integrated pump to top up, or do i need a external pump?

I think the process would be...
* attach hose to the filling valve (upper orange one)
* fill hose with glycol mix, and then submerge it in bucket of glycol mix
* open the filling valve
* run the integrated pump (via setting on the control panel)
* let it run until pressure hits 2bar
* close the filling valve
* let it run for a bit.. and bleed air from the air vent
* top up again if needed

does that sound right?

or will i need to get a external solar pumping unit?

any help greatly appreciated.

I have something similar which I fitted in 2009. It came a a kit of pieces from a now defunct company.

Here is a picture of the filling point. In my case, I have to fill it using a modified garden pressure spray filled with glycol solution. The modification was to take the sprayer from the end of the tube and replace with connector to fit the filling point. It seems to last 10 years between top-ups, so the last time I did it I had to buy another pressure sprayer as the old one had sprung a leak.

However it may be that your proposed method will work. It must depend on the design of that pump, I guess I wouldn't be surprised if the glycol didn't have a lifetime as well.

Anyway I'll let you wait for someone who knows more to come along. Best of luck.

In my case, I have to fill it using a modified garden pressure spray filled with glycol solution. The modification was to take the sprayer from the end of the tube and replace with connector to fit the filling point

Click to expand...

this is interesting, maybe i could use a simple hand pump as well and not worry about the integrated pump


the money i'm saving from the system would be eaten up by the cost of getting professional into service it... its not worth it. either i can do these small topups myself or i just turn the system off

A £10 drill pump should do the job if you de pressurize the EV first.

For simple top ups a simple hand pressure pump is ideal.
Thought if system as been in some time the glycol will really need changing.
It deteriorates due to high temperatures involved .
We did a fair bit of solar thermal at one point now stopped and don't do servicing either.
Way too much hassle.