solar hot water problems

[machmeter62]

In our main solar closet are two tanks, each with a 100 gal capacity or more? Recently our pilot lite failed on the propane heated tank, and no possible re-light was successful! We assumed with this Northern Calif. climate, the solar system would be able to handle the hot water situation? However, we were also told that the "propane hot water tank" must have hot water greater than 100 degrees before allowing the solar system to function? Is this activated inside the tank thermostat, or else where?

If this is true can a plumber bypass or re-route the system without heating the propane water tank first to that minimum temp? We have a solar monitor in the home that monitors the water temp, but at this stage, a 170 degrees on the roof, and more than 110 at the propane water tank, but no hot water in the pipes leading to the propane water tank?

Thanx in advance for your help.

 

[MtHam]

"However, we were also told that the "propane hot water tank" must have hot water greater than 100 degrees before allowing the solar system to function? Is this activated inside the tank thermostat, or else where?" NEVER HEARD OF THIS!

I too have a similar system, the water from the panels circulates through the 1st tank which feeds the standard hot water heater (HWH). If the water coming from the 1st tank is cooler than the thermostat setting on the HWH, then the propane burner kicks on.

Sounds like you might simply need a new HWH. Otherwise, more details of your system layout are needed.

 

[MikeD74T]

mach, You're missing several factors to get a good answer. Does your solar directly heat water or is it a closed loop system. Does your solar tank serve as a preheat tank to the gas fired tank? Are there circulator pumps involved?
I had a close loop solar setup that heated a preheat tank so my propane gaw HW heater was fed with 180 degree water when there was enough sun. The solar instrumentation only controlled the first tank/circulator pump. Depending on how you are plumbed you should get 100% solar in the California sun in summer & at least 50% spring & fall. Can you post some pics? MikeD74T

 

[Egon]

Does the propane heater have a thermocouple on the pilot light? If so this may need changing or cleaning.

 

[machmeter62]

Thank you gentlemen for the replies. The blankets are about 6" thick around the two tanks, and difficult to un-clutter. I think the system is a closed loop? A couple of years ago a freeze valve failed and was dumping a constant small flow of water off the roof; we had no loss of water pressure anywhere....closed loop system? There is a jungle of plumbing on top of the tanks with many valves and no labels. Part of this problem is we use this system for a indoor spa also, but the spa system was added during construction of the home. This system creates several valve movements.

This entire project was installed in a new home in '85 by "Creative Energy," and they left the solar system business, I think?

I would like to send photos, but haven't made that transition to digital cameras yet!
I will try to post a mental picture of the plumbing, but again that maybe be difficult, because of a adjacent furnace located next to the propane tank. I may have to go under the home to find the in-coming water line to the propane water tank. To replace that propane hot water tank will require removing the furnace out first....it's that confining!

 

[machmeter62]

Mike,
I will start un-covering the tanks soon, sofar the only clues for the routing is the two pipes to the roof for the solar panels cold up/hot down with temp gauges and levers too, and adjacent levers for the the spa if wanted. Then the water heads to the large storage tank that has an independent 3/4" GRUNDFOS pump to recirculate the water there. This is located midway down the side of that tank, but the pump has failed. A recent solar service man looked at the situation, and said it's not needed? But no thoughts on how to by pass that 100 degree "fictious" (start-up) problem?

Today with temps in the 60's we had 143 degrees at peak coming from the roof panels. If this is a closed system, how is water ever added after a freeze plug/valve failure, or is that connected to the domestic water line to the home somewhere? Maybe the solar system needs filling to solve some issues?

I was away from home alot when this project was under construction, and regret not having any diagrams or manuals explaining problem solving.

 

[machmeter62]

EGON,
I only recall one successful lighting of that propane water heater. It takes a long special match, or long narrow pliers with a lighted match to reach into that slim cone area for ignition. It has no visible thermocouple, but that is a good point for replacement?

Everything designed or built in this century is passed through a "legal/eagle" office first, to avoid lawsuits?

 

[machmeter62]

MtHam,
We live on the Eastside of "Big Rock Ridge" and our propane server is/was until today when we were going to order more propane. I don't know if this is a new threat, but after my wife talked to McPhails, our server, they now charge in addition to the fuel purchase.....$85 dollars to re-light the propane tank!!

 

[MikeD74T]

mach, As you uncover, look for wire following the pipes. pumped systems usually have a controller with temperature differential sensors (thermistors ??) that sense & compare temperatures at different locations so hot water is not pumped in the wrong direction. You may merely have a bad thermistor. Sometimes you can test thermistors by reversing them & pump will run all the time, depending on your setup.
As for the gas HW tank with a pilot flame, there's a good chance that you just need a new thermocouple. Available at hardware stores , easily changed, & relight should only take a couple of minutes. $85 seems like a lot for the task but it can kill a couple hours for a technician including travel time. MikeD74T

 

[machmeter62]

Mike,
I checked the control panel at exactly mid-night Sunday after a 'mid-sixties" temp. spring-like day here. The panel displayed 110 degrees at the collector, and 110 at the storage tank also. I will get a new thermocouple and report back....it may take awhile....I am always behind the "power curve!" We tried to get hot water, and still locked out, and a new thermocouple with a lighted pilot light will solve the problem.