Friday, March 1, 2019

Electric On Your Solar Water Not Working? Easy Steps to Confirm

There are 2 separate heating systems on a solar hot water system, and they have nothing in common except the water.   They don’t even “know” that the other system exists.

1)      Solar Heating
2)      Electric Backup Heating

You can easily tell if the solar portion is working, using this

For now we focus on the electric backup heating, because having no solar hot water costs you a few dollars a day, but having NO HOT WATER can be a major annoyance.

The disconnect is only occasionally a problem, unless of course, someone pulled out the disconnect to work on the system, and then failed to put the spade connector back in, or put it in upside down. 

If the timer spins (keeps the correct time), then you know that the timer is getting power (and you also know that the disconnect is fine)

If the timer does not spin, then the first thing to check is the breaker.    Breakers can be tricky, they can look not tripped but really be tripped.   So you push them firmly off, and then firmly back on.   Set the timer for the correct time.

Read this to get to know your timer

If the timer spins, and the outside little handle is in the on position, then it should be sending power to the “High Limit Reset” Switch which is on top of the Thermostat (actually part of it, it’s an assembly).     If the High Limit Reset safety switch was activated (by really hot temperature like 160F or 170F) then the power stops right there, and never gets to the thermostat.        It’s a simple “reset” just push the little round Burgundy colored button, and if you feel a very slight click, pay attention!, then it was activated, and now it is reset….your problem is likely solved.

The second red link on this page explains more the on High Limit Reset

How can you tell if the element is actually heating the water?      We call this the “ear test”.    

1)      The thermostat setting must be above the temperature in the tank.
2)      If the tank is fairly warm (say from the Sun), but you want to test the T-stat, you can turn it up to a high temperature by turning clockwise with a small flat bladed screwdriver.   As the setting exceeds the water temperature, you should hear a little click, indicating that it is now sending power to the heating element.
3)      Put your ear right on the tank, if you hear a faint humming, that is the element heating the water.   One caveat though….in rare occasions, you will hear some humming, but the Element will actually be mostly broke, and it really won’t make hot water.     If you hear the humming, but never get hot water, you have a bad Element, OR the below, a bad Mixing Valve.

It can be a real bear to change an element.    It needs special tools, and if you strip it, the whole tank is shot.   Any leakage or rust in this whole area can be a real electrocution or fire hazard.     Just because you have a breaker (sitting in your breaker panel for 30 years, never moving) does not mean that it will work when needed!    

But let’s finish on the Thermostat.    If you turn the T-stat all the way up, and it never clicks indicating sending power to the element (and everything upstream is OK, breaker, disconnect, time, high limit reset), then the T-stat is likely bad.    If you have an electrical tester, and the knowledge to use it safety, you can read the voltage into the T-stat, and the voltage to the Element, both should be 240V AC. 

One thing that will confound even the best troubleshooting in the world, is the Mixing Valve.     If the Mixing Valve (MX) has gone bad and gets occasionally stuck, nothing else that you do or change will make the system work well and consistently.     MX is usually reliable, and a bit pricey to change, it’s $315 labor and material to change, unless repiping is needed then it is more.    So when nothing else makes sense, and especially if system is over 7 years old, then it’s time to bite the bullet and replace the MX.    The MX is usually a red colored cap in the top center of tank (sometimes blue or green).

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