Looking to replace solar water heater

[inetdog]

The OP will have to correct me but I believe the stuff he is referring to is put into the toilet for off season freeze protection (very inexpensive). If it for the rad in the RV, typical temps are sub 100C.

Typical is one thing, but the reason that engine coolant systems are pressurized (up to ~15-20 psi) is to allow for the coolant to get above 100C under heavy loads. The "typical" temperature is at least as high as the thermostat setting on the system. It is true that you never expect the coolant to actually vaporize and re-condense however.

[MikeSolar]

RV use does not see high temperatures?

The OP will have to correct me but I believe the stuff he is referring to is put into the toilet for off season freeze protection (very inexpensive). If it for the rad in the RV, typical temps are sub 100C.

[inetdog]

RV use does not see high temperatures?

RV engine radiator sees high coolant temperatures. RV plumbing to be protected when you winterize the system does not. What is the product labelled for?

[russ]

RV use does not see high temperatures?

[MikeSolar]

Me thinks you have no idea of what you are talking about.

I have bought propylene glycol here for prices like you are talking about. To the best of my knowledge it is all the same.

I wasn't talking about pricing. I am only talking about formulation. I too buy glycol and I buy it from Tyfocor by the IBC (1000l) and I know the pricing. I worked with Schott when they were making the high temp vacuum tubes that Viessmann, Vailant and others sold AND I know the difference between some of the formulations for high temp stuff.

My old company also has glycol formulated specifically so that additives will go back into suspension after steaming out. RV stuff is not the same.

Pricing for glycol is different in Europe because the solar market is 100 times bigger, people change their glycol every few years while most people here forget about it. It is the same with lots of products. Market drives price.

So, if I am wrong, tell me the difference between Tyfocor L, GL, GLS? it is not the base product, it is the additives.

[russ]

The difference is that the RV stuff is formulated for freezing and not for high heat. At high heat expect the additives to precipitate out and mess up the system.

Me thinks you have no idea of what you are talking about.

I have bought propylene glycol here for prices like you are talking about. To the best of my knowledge it is all the same.

[MikeSolar]

It did not come in powered form, it looks the same except for its pink. Would you still say its not safe to use? It was $125 cheaper I paid less for all five gallons than one gallon of the stuff from my plumbing supply store.

The difference is that the RV stuff is formulated for freezing and not for high heat. At high heat expect the additives to precipitate out and mess up the system.

[ardcarmvk]

The proplyene glycol is good but the RV stuff sometimes comes in a powder form and I would not use it. In your area, -50 is not needed. 30% concentration is appropriate. We only use 40% (Ontario Canada) and the higher the percentage the harder it is to pump so if you mix down use distilled water and see if the local solar guy can check the concentration.

It did not come in powered form, it looks the same except for its pink. Would you still say its not safe to use? It was $125 cheaper I paid less for all five gallons than one gallon of the stuff from my plumbing supply store.

[MikeSolar]

I found the replacement model# ealier on grunfos' site and picked one up. I also found polypropylene glycol for a good price. 5 gallons premixed at my plumbing supply store was $150, I got some RV/Marine polypropylene antifreeze, good for copper pipes premixed same -50 degree rating for $4 a gallon. I will try to unstick the pump and save the $180 there too. I was going to use the uhaul pump to pressurize the system but a local solar guy will come by and use my glycol for hourly labor.

The proplyene glycol is good but the RV stuff sometimes comes in a powder form and I would not use it. In your area, -50 is not needed. 30% concentration is appropriate. We only use 40% (Ontario Canada) and the higher the percentage the harder it is to pump so if you mix down use distilled water and see if the local solar guy can check the concentration.

[ardcarmvk]

I found the replacement model# ealier on grunfos' site and picked one up. I also found polypropylene glycol for a good price. 5 gallons premixed at my plumbing supply store was $150, I got some RV/Marine polypropylene antifreeze, good for copper pipes premixed same -50 degree rating for $4 a gallon. I will try to unstick the pump and save the $180 there too. I was going to use the uhaul pump to pressurize the system but a local solar guy will come by and use my glycol for hourly labor.

[MikeSolar]

I'm pretty certain, that a water bed pump from Uhaul, will disappoint you. Look for the grundfos up15-18su pump on amazon, see what replaces it, and use that. I've also heard that the magnetic coupled impellers sometimes get stuck on a piece of grit, and stop pumping. Just pull the pump, use a pencil to un stick it, and back in business. Buy a spare, and keep the old one to use as a backup if the new one fails in 10 years.

The Grundfos is not a mag coupled pump. How old is the glycol, if it is 6 years or more, it will be worth it to replace it, and not that expensive. You can do it yourself if you are worried about cost. Mike is right tho, after draining, the impeller can often be unstuck with a pencil. Barring that, the 4 allen screws, 3mm, I think and be removed and the can can be removed from the pump body to expose the impeller.

[Mike90250]

I figured out that my glycol side grundfos up15-18su is not pumping anymore. I checked for voltage to it and that is good. I don't see anyway to unfreeze it if it is stuck. If I replace it, can I flush and change the glycol myself? Would you recommend just paying someone? I was thinking about reading up on it and use a waterbed pump from uhaul. It has the hose bib connections and it looks similar to one of my instruction pics.

All this cost is adding up quite fast.

I'm pretty certain, that a water bed pump from Uhaul, will disappoint you. Look for the grundfos up15-18su pump on amazon, see what replaces it, and use that. I've also heard that the magnetic coupled impellers sometimes get stuck on a piece of grit, and stop pumping. Just pull the pump, use a pencil to un stick it, and back in business. Buy a spare, and keep the old one to use as a backup if the new one fails in 10 years.

[MikeSolar]

I figured out that my glycol side grundfos up15-18su is not pumping anymore. I checked for voltage to it and that is good. I don't see anyway to unfreeze it if it is stuck. If I replace it, can I flush and change the glycol myself? Would you recommend just paying someone? I was thinking about reading up on it and use a waterbed pump from uhaul. It has the hose bib connections and it looks similar to one of my instruction pics.

All this cost is adding up quite fast.

Is the pump spinning? If you don't know, you can unscrew the end of the pump and see if it is by putting screwdriver in just to touch. If it is spinning, you don't have enough static pressure to get it up to the roof and/or you have an air bubble up there. Either way you need more glycol or turn it off because it will burn out.

[ardcarmvk]

I figured out that my glycol side grundfos up15-18su is not pumping anymore. I checked for voltage to it and that is good. I don't see anyway to unfreeze it if it is stuck. If I replace it, can I flush and change the glycol myself? Would you recommend just paying someone? I was thinking about reading up on it and use a waterbed pump from uhaul. It has the hose bib connections and it looks similar to one of my instruction pics.

All this cost is adding up quite fast.

[Naptown]

Disconnect the lower element at the lower thermostat the element side of the thermostat. With the lower element connected it will heat the lower portion of the tank and will defeat the solar until it gets really hot.
Remove completely the wire between the lower element and lower thermostat.

Remove the red wire from terminal L4 and black wire from terminals T4 as shown on page 2 of the instructions you posted in the attachment above.

This will leave the top element operational and remove the lower element from the circuit.