Many of solar contractors are using standard temperature differential controller in their drain-back installs.
Hey, what do you mean Viktor by saying "standard"? - are asking me my customers, - the differential controller is a differential controller...
Well: - "Is the delta T controller is only control you install on your drain back system?"
- No, we're adding a time delay relay for booster pump and high limit switch to prevent excessive steaming and noise, - is usual the answer.
Ok, but now my friends, we got a solution!
The DeltaSol DB series controller
manufactured by RESOL (www.resol.com) is designed to operate drain-back systems
more effectively. It is available with single or dual
relay output and looks a like well
known DeltaSOL BS controller, but offers
smart control logic and options not available
before from anyone in single package.
First of all, to prevent unwanted stop and go
on start-up, the system is monitoring time - how long is the start up condition (delta T -ON) is present. It is called initialization time.
After that, the solar pump and booster pump (in DB3 only) will start fill-up the collector circuit. The filling time is adjustable and if it expires the booster pump will switch off and whole operation will monitored in stabilization mode for pre-set period of time. It again prevents unwanted pump stop if delta T goes down for a short period of time.
Collector temperature high limit is pre-set for 95C (203F) preventing any steam flushes and banging noise in pipes.
All other nice futures like energy metering, operating hours counter and collector low temperature limit are in.
DeltaSol DB1 (single output) and DB3 (dual output) are now in stock.
Propylene Glycol is an effective ant- freeze agent. However, when improperly added to the system can be too weak to be effective and allow freeze-ups, or to strong so as to create complications of corrosion, and contamination of the potable water supply.
