Solar heat in parallel w/ gas?

[wetviking]

I've been running a 4'x20' solar panel for the past 3 years and the family has finally persuaded me into getting a gas heater. So I'm taking an advance on my $10 per week stimulus and bought a Hayward 100k heater. Question is, I'd like to experiment and run this gas heater in parallel with the solar heater and thereby reducing my gas cost since the water entering the gas heater from the solar panel would be a bit warmer (on sunny days) - my concern is that this would create too much head flow and would hamper actual filtering. Any thoughts? Has anyone tried this?

Regards,
Wetviking in Chicago

[CarlD]

I've been running a 4'x20' solar panel for the past 3 years and the family has finally persuaded me into getting a gas heater. So I'm taking an advance on my $10 per week stimulus and bought a Hayward 100k heater. Question is, I'd like to experiment and run this gas heater in parallel with the solar heater and thereby reducing my gas cost since the water entering the gas heater from the solar panel would be a bit warmer (on sunny days) - my concern is that this would create too much head flow and would hamper actual filtering. Any thoughts? Has anyone tried this?

Regards,
Wetviking in Chicago

You may consider using a different return for the solar panels. I believe the gas heater will be in-line, but my solar panels are Tee-d off the main return so they get their own flow. To prevent leaks you may well have to restrict the flow to the panels (I do--I can NEVER run wide-flat-out our my panels with burst). I have a separate return for my panels. If I were you, I would tee the solar panels off BEFORE the heater, so you never get hot water going into the panels--otherwise you won't get efficiency from either the heater OR the panels.

[wetviking]

Thanks Carl, I think I'll experiement a bit once the gas heater is set up.

[Poconos]

Any kind of multiple heating configuration you always want the heaters in parallel, not series. You get maximum heat transfer from the heat source, whether it be gas or sun, to water when the temperature differential is highest. Thus you don't want to run pre-heated water into a gas heater or the other way. The only thing you'll have to watch is to maintain enough flow through the gas heater so it doesn't trip off for low flow.
Al

[CarlD]

Any kind of multiple heating configuration you always want the heaters in parallel, not series. You get maximum heat transfer from the heat source, whether it be gas or sun, to water when the temperature differential is highest. Thus you don't want to run pre-heated water into a gas heater or the other way. The only thing you'll have to watch is to maintain enough flow through the gas heater so it doesn't trip off for low flow.
Al

I TRIED to say that but Al put it so much more clearly.

To this I'll add: It's not temperature that heats your pool, it's calories or BTUs (metric vs English). Every BTU warms your water. I split my own system in two to increase flow over temperature. If it was practical, I'd split it again into 4 units. Plus, I get to turn on the units in the sun and turn off shaded units.