Time for some maintenance on the floor heater.

[gayler]

My floor heat has been working flawlessly for over twenty years. I noticed today that the expansion tank has developed a small leak. My existing tank is a condraco 16-xt5-01 6.34 gallon. How critical is the size of the tank? The heat source is a 50,000BTU 50 gallon natural gas water heater. I replaced the anode once about 10 years ago. I wonder if I should replace the heater too as a precaution. I might want to replace with a tankless heater. I wonder what flow rate and BTU rating I should use. Most tankless I have seen are much more than 50,000BTU.

 

[chinboys]

A 5 gallon boiler rated expansion tank installed vertically and pressurized to match 15 psi or at least to the water heater's temperature pressure safety valve is what I would do.

 

[Jackfre]

Temp and pressure being directly proportional exp tank size is important. don’t mess with success. Replace like for like at the correct pressure. You don’t say if you are running at line pressure or reduced. Is it a dedicated tank or shared use? Your tank gives you the advantage of a large pool of supply water. Careful in going tankless. Most manuf specifically exclude them from use in closed loop space heating. The best option for you is to go to a wall hung boiler. Many manuf offer 50-65kbtu inputs and go up from there. Pick up Dan Hollahan’s excellent “Primary Secondary Piping.” You have some time before the fall season so research it well.

 

[fitter30]

Ex tank air charge should match the system pressure under 100°. Would also be a good idea add some boiler treatment.

https://www.google.com/aclk?sa=l&ai=DChcSEwjg76G41qiEAxU1OdQBHTmXAtgYABAMGgJvYQ&ase=2&gclid=EAIaIQobChMI4O-huNaohAMVNTnUAR05lwLYEAQYAyABEgIqcPD_BwE&sig=AOD64_3zks0lnWgf3XiKsC1F54g57MgtVw&ctype=5&nis=4&ved=2ahUKEwiivJq41qiEAxXb4skDHWg-D2EQwg8oAHoECA0QCg&adurl=

 

[gayler]

Temp and pressure being directly proportional exp tank size is important. don’t mess with success. Replace like for like at the correct pressure. You don’t say if you are running at line pressure or reduced. Is it a dedicated tank or shared use? Your tank gives you the advantage of a large pool of supply water. Careful in going tankless. Most manuf specifically exclude them from use in closed loop space heating. The best option for you is to go to a wall hung boiler. Many manuf offer 50-65kbtu inputs and go up from there. Pick up Dan Hollahan’s excellent “Primary Secondary Piping.” You have some time before the fall season so research it well.

Thanks for the reply! I was getting to try for exactly the same pressure tank as what I have now. As for pressure it is usually below 15psi when hot. I’m not sure if I will replace the existing water heater. Just wondering as it has been in service for around 20years. With a 50 gallon tank that would make quite a mess is it sprung a leak not to mention the cost of the coolant! One other thing when this heater was put in the company that I dealt with did not include any automatic shut down if the system was low or empty of coolant. What would be needed? Some kind of fluid level switch?

 

[Sumboodie]

Thanks for the reply! I was getting to try for exactly the same pressure tank as what I have now. As for pressure it is usually below 15psi when hot. I’m not sure if I will replace the existing water heater. Just wondering as it has been in service for around 20years. With a 50 gallon tank that would make quite a mess is it sprung a leak not to mention the cost of the coolant! One other thing when this heater was put in the company that I dealt with did not include any automatic shut down if the system was low or empty of coolant. What would be needed? Some kind of fluid level switch?

Yeah, low water cutoff or a low pressure cut off