Solar Thermal Maintenance Visits - What do you charge?

[Worcester]

We're getting a lot of requests to carry out maintenance visits on Solar Thermal systems - interestingly they are mostly Worcester Bosch systems and all are with soldered joints, and every single one has at least 3 other elements not compliant with current standards above and beyond the solder.

So couple of questions from those that have been doing solar thermal longer than us
1) When did soldering stop being allowed (I know 5% silver 95% tin is allowed, these SEEM to be ordinary solder)
2) What do you typically charge?
- We are draining down, flushing old glycol out with water and then going through a normal new system commissioning process including pressure testing, new glycol, flow rate setting, checking controller settings etc. - This can easily take 3-4 hours excluding travel, from site arrival to departure.
So far about 50% have shown a leak under pressure testing somewhere - we have repaired to current standards - either compression or solar rated xpress.
We would then charge extra for those fixes (on a time basis) plus materials.

 

[Gavin A]

1 - I trained in 2008 on it, and it weren't allowed then, though I suppose that was more of a guide than an 'allowed'.

2 - £150 basic flush and fill, plus hourly rate and parts charges after 4 hours, £250 if it involves more than one operative.

 

[solarsavings]

I did the worcester course in 2005 and there system at the factory was plumbed in with 22mm copper and a mix of soldered and compression joints. My own system has been in since 2005 in 10mm copper with solder/compression joints. Mick Lyons from the nearby town of March, once head of the sta, has many systems installed since the days of phillips tubes then thermomax. I've seen lots of his his systems, still working, plumbed in in 15mm copper and with what must have been soft solder.

We also have a lot of system installed with soldered joints and have never had a problem. I have been out to many a system with low pressure where the fibre washers on stainless flexible pipe have failed.

 

[solarsavings]

Incidentally, I have an old customer coming up from Somerset in he morning to collect 30 replacement heatpipes for the old solfex collectors. He phoned me a few week backs to say his system had ceased to work at all this year. After going through a few checks on the phone I asked him to drop a few tubes to check the hp's for frost damage. One to look out for.

 

[Gavin A]

I did the worcester course in 2005 and there system at the factory was plumbed in with 22mm copper and a mix of soldered and compression joints. My own system has been in since 2005 in 10mm copper with solder/compression joints. Mick Lyons from the nearby town of March, once head of the sta, has many systems installed since the days of phillips tubes then thermomax. I've seen lots of his his systems, still working, plumbed in in 15mm copper and with what must have been soft solder.

We also have a lot of system installed with soldered joints and have never had a problem. I have been out to many a system with low pressure where the fibre washers on stainless flexible pipe have failed.

I think it depends a lot on the stagnation temperatures. Stagnation temperatures can be a lot higher on the evac tubes than on flat plate collectors, I've seen some extremely high temperatures coming in from the roof down the pipes from our system in stagnation (we have an 80 tube system), I think I've seen 180degC, and was really glad of the compression fittings when dealing with it as at least I knew there was no chance of them hitting melt point and suddenly popping on me.

the other key issue I've noticed a fair amount is the white versions of the expansion vessels going pop a lot, as they seem to only be rated to 110deg, vs around 130 for the red vessels, yet both are listed as high temperature rated. I think half our call outs are related to that issue.

 

[jason121]

Strange that this should be mentioned. I had two last week to repair, both customers have not come back to me after my first visit assessing the faults.
One system was split North east and South west. Pressure had dropped the other was on a 2 bed bungalow with around 24 tubes on a 169 litre cylinder. Blow off went out side and filled with water. Company who installed this wanted £1500 to repair and don't do warranties. Solarsavings know who they are. I charge a full day to plus parts to service these systems.

 

[solarsavings]

Jason, are they still in business? I did check some while back and they had been removed from the mcs register.

 

[jason121]

They are both still in business Mr WoodCOCK and Mr Gedney

 

[The Solar King]

It all depends on the systems. I recently won a contract for a Housing Association to maintain all their systems. The vast majority are Viridian Drain back where maintenance is minimal. The annual service is little more than visual inspection and top up if necessary. We also check the unvented cylinder at the same time. We can do six a day with no trouble and priced accordingly. The rest are Glow Worm pressurised using a basic Resol controller and PAW pump station. Annual service is again straight forward.

All repair work is an additional charge at our hourly rate.

Five year fluid change hasn't come round yet, but can be done in an hour.

Nice work if you can get it.

With regard to soldering, can be allowed on some systems with high temperature solder. However I only use mechanical fittings whether 10mm or DN16 (and sometimes copper from controller to cylinder).

Interesting to see the birds come home to roost on evacuated tubes. Have never fitted them and never will. The empirical evidence on superior performance is marginal. More importantly, the aesthetics are dreadful. Who in their right mind wants to make a building (especially a house) look like the local tanning salon have dumped a sunbed on the roof?

 

[Worcester]

Many thanks for the replies.

Saw 160° as the stagnation temp on a plate system yesterday.

We've been same kind of rate as you Gavin, plus materials - these all have never had the glycol changed, so as above we flush out and then recommission, it takes about 3 hours with all the checks and then having to drain down and fix faults and test again can add an hour easy - so if there was a lot we could do 2 in a day - so far they have ll been pressurised systems using the Worcester TDS10 solar controller. - Must have been good sales rep around here!

 

[jason121]

How do you guys fill the solar thermal. We do have a filling and flush pump but sometimes can be a pain to drag upstairs and my pipes never reach the filling loop on the pump station. Be interested to hear how you guys do it.

 

[The Solar King]

Resol Befulstation. And yes, it is a pain if the pump and filling point are in the attic! Can still get it through the hatch. Thankfully pipes have always been long enough.

 

[solarsavings]

We use filling/flushing pumps with or without the tank if the pump station is in the roof space.

 

[Worcester]

aha - our filling station is custom build specifically to fit through hatches, we also added remote control switches and have plumbed / piped it so that we can use separate tanks (aka 25 litre camping water carriers with hose connections on) works brilliantly as we can pas the unit up empty and use the pump station to fill from the carriers and then switch over. We also have long hoses so can flush from outside and only put up in the loft for the final fill, de-aerate and pressurise. All the rest done from outside if possible.

 

[The Solar King]

Excellent. How about some photos?

(In Hawes for biomass course)!