Using a water heater for thermal storage

[jblnut]

I have a relatively new water heater that we are no longer using and I'm curious if there's any reason why it could not be used to add a little capacity to my boiler system?

It has an anode rod in it that is in fairly good shape and the biggest question I have is if it will cause issues with the "control" product that is in the water to stop corrosion in my boiler system.

I would plumb the tank in on the return side coming from my farm shop as the return temps are sometimes below 140° f and this would hopefully help temper it a bit before it goes to the wood stove.

I have seen threads on here about using all kinds of different things as thermal storage tanks and I'm wondering if anyone has done it with a water heater and if the anode rod should be left in or removed.

Thank you in advance for any advice!

 

[Easy Livin’ 3000]

I have a relatively new water heater that we are no longer using and I'm curious if there's any reason why it could not be used to add a little capacity to my boiler system?

It has an anode rod in it that is in fairly good shape and the biggest question I have is if it will cause issues with the "control" product that is in the water to stop corrosion in my boiler system.

I would plumb the tank in on the return side coming from my farm shop as the return temps are sometimes below 140° f and this would hopefully help temper it a bit before it goes to the wood stove.

I have seen threads on here about using all kinds of different things as thermal storage tanks and I'm wondering if anyone has done it with a water heater and if the anode rod should be left in or removed.

Thank you in advance for any advice!

Like your idea.

An electric heater would be better than gas, as the gas has an- always open- exhaust hole that constantly leaks heat. If it's gas, you could plug the hole with something that will close and insulate it, since you don't need it anymore.

I'd leave the anode in to protect the steel tank. I'm no expert on this topic, but I'd leave it in.

 

[sloeffle]

Is the boiler a IWB or a OWB ?

 

[jblnut]

Is the boiler a IWB or a OWB ?

Gonna go on a limb and assume Indoor or Outdoor ....

I have a Crown Royal 7400MP non gasifier. So I'd say that's an OWB.

I'd say 350gal of water between the boiler and lines and such. The goal with a little more storage isn't to fire it up everyday and let it all cool off but more to soften the blow with the return water going back to the stove. A water heater gets 50f water dumped into it when it's a water heater so 120f water going into 185f water should be okay as well I'd think.

 

[sloeffle]

Looked at Crown boilers last year when I making my decision on what to buy, they make a nice boiler. Personally I'd be a little leery of putting a hot water tank inline with my boiler because I'd be afraid I'd pick up a bunch of crud from anode rod, or the tank itself. If you do use the tank I'd definitely put a filter between the tank and any exchangers. You don't want your high dollar exchanger(s) getting plugged up with stuff that could have been stopped by a Rusco spin down filter.

When I have a call for heat, and a call for hot water I'm seeing temperture drops around 30° sometimes ( 50k BTU roughly ) my return temps are getting close to 140F. My plan is to install a Danfos ESBE, or (broken link removed to https://store.tarmusa.com/products/lk-823-thermovar-1) for return protection. I called Tarm Biomass a few weeks ago and asked about the ThermoVar and the gentlemen I spoke to said it's rated for 10GPM and will ensure that return temps are above 140F. I'm a firm believer in the KISS method, a mixing valve fits that bill also.

 

[jblnut]

Looked at Crown boilers last year when I making my decision on what to buy, they make a nice boiler. Personally I'd be a little leery of putting a hot water tank inline with my boiler because I'd be afraid I'd pick up a bunch of crud from anode rod, or the tank itself. If you do use the tank I'd definitely put a filter between the tank and any exchangers. You don't want your high dollar exchanger(s) getting plugged up with stuff that could have been stopped by a Rusco spin down filter.

When I have a call for heat, and a call for hot water I'm seeing temperture drops around 30° sometimes ( 50k BTU roughly ) my return temps are getting close to 140F. My plan is to install a Danfos ESBE, or (broken link removed to https://store.tarmusa.com/products/lk-823-thermovar-1) for return protection. I called Tarm Biomass a few weeks ago and asked about the ThermoVar and the gentlemen I spoke to said it's rated for 10GPM and will ensure that return temps are above 140F. I'm a firm believer in the KISS method, a mixing valve fits that bill also.

I have a spin down filter with a purge/drain valve on the bottom that I've blasted stuff out of twice now that it's been running for a while. It's in the house not the shop but it's on the incoming line in the house so those exchangers are protected. When I plumbed the shop I put a set of valves in so I could add another heat exchanger of sorts BUT I put them on the incoming side so I'll have a little plumbing to redo. I could certainly put another spin down filter in using the bypass that those valves creates to protect the exchanger in the shop. I thought one filter in the system was good enough but didn't think it that far through I guess ...

The mixing valve you linked is more intriguing than anything .... it'll go between the supply and return in the back of the stove and keep the return water at least 140F. That is neat. Didn't think of that when I was putting this all in .... A mixing valve would accomplish what I want to do as well. I have a mixing valve on both infloor systems and they're both turned down almost all the way and are running 90F water through the floors and the return temps are still below 140F sometimes.

Thank you for the reply and insights. Gives me something to think about.