20 year old water heater trouble

scrantch

Hi everyone, just wanted some opinions on the best way to set up a heating / dhw combo. Either everyones too busy or when they see how tight everything is they don't want the hassle. I've seen a lot of talk on here about my same trouble. Have a fifty gal. Polaris water heater doing dhw and floor heat through a plate exchanger. Had ignition troubles from day one. Igniters, boards, sensors, have all been replaced more than once. Except for too few zones, because i use a wood stove,(thank god), everything seems fine except the constant worry if i come home with the board lights blinking on the polaris. Considering lack of space, would anyone recommend a combi tankless boiler? Or am I looking for more problems with those.
Thanks in advance
Scrantch

GW

If you’re tight on space then Combi is the answer. Time to put your worry aside. Also can’t you get a WiFi gadget to alert you if the heat drops out? It’s the modern era!

I like tanks much better but if there’s no room there’s no room

scrantch

Thanks GW, there is room for the 50 gal polaris but what would you replace it with? I need about 150kbtu because this one don't keep up when cold out . 120 out 70 return and it never catches up on floor heat

Jon_blaney

Is this oil or gas?

GW

I don't understand, i thought there was just enough room for one unit. If you have room for two- I would always recommend the boiler and indirect water heater. Yes, 50 degree drop, that's quite high. No ground water issues?

DZoro

Lochinvar Noble, if you have a local contractor that handles them.

scrantch

GW, there is enough room for the big water heater but no room to install anything else along side it. I was advised to put bigger circulators to close the delta t? The original installer retired. It's 2500 sq ft ranch slabon grade. No water. 5 400 foot loops in 2 zones . I'm in Monroe Mass if you want a job? I can send pic if interested

scrantch

Jon_blaney said:

Is this oil or gas?

It is propane

scrantch

If I used a combi boiler I could delete the plate exchanger correct?

HVACNUT

Stackable EK Frontier with the Carlin EZ Gas for LP.

DZoro

Yes if you use a combi you could get rid of the plate H/E.

neilc

before you get rid of the plate exchanger,
make sure your radiant is 02 barrier

scrantch

The Polaris does fire if I kill the power to it and turn it back on. So ì have a spare igniter and board to get me by until i can find someone who will show up and can get it done right. I had a plumber who came with his rep from a distributor back in May, I figured if was too busy then, he must be swamped now. The rep measured everything, understood the problems, suggested leaving the circs on all the time with a different control.... on and on, but that's the last I've heard from them.

scrantch

neilc said:

before you get rid of the plate exchanger,
make sure your radiant is 02 barrier

It's definitely not. It is 7/8 " poly pxc. Never liked the idea of partially cross linked pex so everything had to be stainless

DZoro

Sorry plate set up has to stay. Will have to be set up like 2 separate systems.
D

scrantch

I wish this Polaris would be more dependable. Everything seems to be designed well except the pc boards and igniters.

GW

Thank you, Monroe is a bit outside of our normal radius. We are good for 25 to 30 minutes one way. After that I need I stack on time and it’s just not super good. Plus future maintenance would be hard for us to be top notch.

So yes keep the flat plate for your non o2. I thought it was the appliance not burning enough btu, is it? That large delta means not enough flow or not enough BTU. I bet the HX is the issue. You may need a larger HX

Can you measure the temp drop on the appliance side of the HX?

OR is it the flat plate does the dhw and the tank does the floor?

scrantch

150 to 100 on water heater side. 130 to 70 on floor side. The dt gets closer after it runs awhile. Yes the hx does the floor. These are just measured from a cheap laser but you see the spreads anyway

scrantch

Thanks Gary, I hear the same travel issues even from North Adams

scrantch

The circulators are UPS 15 55 suc. One does 2- 400 foot loops the other 3 -400 foot loops

GW

That’s seems Ike plenty., it’s not the system pumps

What’s pumping the water heater to Hx?

GW

LOL North Adams is pretty close isn’t it?

scrantch

A 15 18 su

scrantch

scrantch

You can see in the first pic the plate is 4" thick. It prbably cost more than the boiler

GW

I’m all confused, the two 15-55 are regular pumps? Don’t you want brass bronze stainless on the non O2 ?

scrantch

The 15 55 are ss and so is the 15 18 su. And the heater tank I hope. They are i just checked, they are union mounted

scrantch

They made me buy all ss in order to run a direct system, then the inspector said i couldn't do it that way. Back when the house was built in 1998. Also had to use cu for domestic, no pex

Jon_blaney

How do you control the floor loops? Are the in the slab? Do you turn off or set back the infloor loops?

scrantch

I have no control of that. One pump goes to a three tube manifold, the other to a two. Everything goes to the slab.

GW

Ok well get a new Combi and ditch the ss pump to the HX. You need more pump, a regular pump is less costly.
If you want a real deal radiant system you should consider a smarter control like Tekmar. I have a 420, 741 and 552 at my home

scrantch

If the guys who came don't get back to me, at least with a recommendation of what he think needs to be done, can I run it by you on here? He did mention a control that constantly ran the zone circs and only ran the boiler circ when it called for heat. I didn't say anything but it didn't sound good to me. But what do I know.

scrantch

Also do you still need the combi if I will be using the hx? It's set up with a mixing valve to drop the domestic temp now.

GW

Yes we all can offer our opinions

If you get a new Combi then things change. Now, the new unit makes one temp for heating and also it knows when you’re using hot water. So no need for a mixing valve on the domestic hot water

The new boiler also could have a constant circulation setup with both indoor and outdoor feedback

If you keep the existing setup you need a bigger pump and smarter controls would help too

scrantch

Thank you very much everyone. I will be in touch

scrantch

I have to replace the igniter on the polaris for now. I'm trying to figure out if a ups15 42 su, which I happen to have in stock, would pump more than the up 15 18 su. They both draw .74 amps. Maybe the 15 42 is just a 3 speed version of the same pump?

GW

you're dropping 50 degrees, that's too much (normal conditions). Was that after the floor was on for a long time? Too many variables to have exact comments here. Seem like you need a bigger pump. Or, just throw the basic shelf pump (cheap) on and wait till you cab get a better system installed.

scrantch

Thanks GW, I will get larger pumps to get the delta t down on both sides of the HX. And keep fighting with the Polaris heater for now. I read that turning up the heater temp helps with ignition failures. It just seems like a waste to use hotter water to just mix it down to usable temps.
I have another thread to start about another issue in the same house.

GW

ok but the system-side is high drop because the source side pump is too small.