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Swtich to tankless

M

MikeV

Member
I cut my gas bill by over half by switching from the old boiler to tankless water heaters. 2 Takagis for 5 bays s.s. and 1 auto presoak. All the high pressure in the s.s. bays is heated.
 
Mike,

I built my wash with only tankless WHs. I use about 35% less NG than my buddy's wash with the old inefficient tank heaters.

BTW, remember to disable the flow-restrictor valve. These units try and maintain temp and if they cannot, they'll restrict flow, thus starving your pumps. By disconnecting the valve, flow will be maintained, but temp will drop.

Hope this helps...BigLeo
 
Leo, I assume you are talking about Rannai heaters? Aren't they the ones with a flow control valve? I am about to swap out my old conventional heaters for tankless and would like to know where this flow valve is located or what it looks like. What controls it - electric? When you disconnected the valve do you mean unhook the electric to it?
 
Mike, how are your tankless heaters plumbed? Do they work with a circulator pump to heat water in your SS reservoir? Or do they heat the water line feeding the pump stand? I am trying to figure out how to plumb my JCC pump stand for tankless heaters. My pumps are fed by street pressure and my hp soap & wax are fed from my reservoir. So I can either heat the reservoir (hp soap & wax) or my rinse water by hooking into the line that feeds the pump solenoids. Any info or suggestions on plumbing hookup for tankless heaters would be appreciated.
 
I'm about to help someone replace a boiler with a Paloma PH28C, which by itself doesn't have enough flow for his 4 bays, but we're going to use a tempering valve to make it work. Since the heater can make at least 5 GPM of 140? water, the tempering valve will need to add a lot of cold to bring it down to a usable temp, and the combined flow should be more than enough for 4 bays. Once it's set up I'll try and figure out its peak flow.

We were going to use the Paloma as a recirculating heater in the holding tank so its flow wouldn't be an issue, but it requires at least 15 PSI.
 
Reds, I have the tankless water heaters plumbed in series and fills a 55 gal reservoir with a Jobe float valve, this gravity feeds the pumps. The water cools if not used for a long period, but quickly heats up when the first customer starts using it.
 
MikeV said:
Reds, I have the tankless water heaters plumbed in series and fills a 55 gal reservoir with a Jobe float valve, this gravity feeds the pumps. The water cools if not used for a long period, but quickly heats up when the first customer starts using it.
Click to expand...

I have a very similiar setup. I have separate hot (tankless) and cold lines, each with their own float valve that feed my reservoir. When not it use, the reservoir cools to the room temp of my ER. Once in use, it warms up pretty quickly.
 
Let's see some pics. I would like to see some setups if possible. Both of my boilers are 20 years old, this could help quite a bit in becoming more efficient.
 
I just finished an install of 2 heaters on a recirculating system that pulls out of the holding tank, heats up to 120 deg in about 5 min then we put it on a timmer so from 10:00 pm to 7:00am no hot water, the customer loves them.
 
What did you use for a pump? I used a pump that Rannai recomended and it won't pump enough to turn the heater on. But I may have a defective flow control valve in the new Rannai.
 
I used a TACO pump, the feed and return lines are 1 1/2 and both heaters tie into them. Are both heaters not comming on or is it just an issue with one. What size pump do you have, i will look up the pump number and get back to you
 
My pump is a Bell & Gosset NRF-22 (Grainger # 4RD04). It pumps 10 Gal/min at 8' of head, 14.9 GPM at 5' of head. My heater is mounted 4' above the tank, right beside the pump stand. When the aquastat in the tank calls for heat the "in use" light on the Rannai will come on sometimes, but usually not at all. I disconnected the pump and hooked a water line at city pressure to the inlet plumbing and the light came right on. That tells me the pump is too small, or more likely the flow control is sticking. Rannai's application engineer specified a smaller pump than the one that I am using. The email from the Rannai engineer is in my file at the wash and I will double check the specified pump today when I get there. I am using one Rannai 190,000 BTU to heat the SS resevoir (about 15 gallons) for 2 SS bays. With the JC equipment it does not use the resevoir to feed the hp rinse cycle.
 
What size pipe are you feeding the heater with, and what size return back to the tank? Are you pulling out of the bottom of the tank from a bulkhead fitting to feed the circulator, or is the pipe just running down from the top of the tank? sounds like you have a flow problem, the pump you have sounds about right, i am out of state on a job should be back today i will give you my taco pump number. Do you have a pic of how you plumbed this heater. i just looked up you circulator and is does look small compaired to what i used, also i was told to use a bronze circulator by taco for what reason i dont no but they said a cast iron would not hold up, called the office the circulator used was a taco009B
 
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