22Apr
Posted by: Simon In Solar Thermal
We recently completed a service on a solar thermal system installed by another company who, sadly for the client, is no longer in business. The pressure had dropped to nought, the pump was making an awful noise and the system had stopped producing hot water. It became clear the reason there was nothing showing on the gauge was that the pressure relief valve had failed and dumped the glycol. Curiously, the failed valve was attached to the manifold on the roof and the situation was made more awkward by a PV array had been added alongside the collector.
A electrifying service
In order to reach the dysfunctional valve we first had to remove two PV panels from a flat roof below the collector, then erect a tower scaffold to gain access to the main roof, then remove the adjacent PV panel. After that it was plain sailing – we replaced the valve, emptied some of the dirtiest glycol we’ve ever come across, flushed the system out then refilled it with fresh, new Solaris PGC (our current glycol of choice). After taking down the scaffold and re-laying the PV panels, we were pleased to note the solar thermal pump was running quietly, transferring heat from the collector into the cylinder, just as it had when it was installed over eight years ago.