indirect question

Hilly

The boiler is a Saturn by Granby Industries. Their literature is very poor.

I have been asked to add an indirect in replace of the coil and add air elimination to this poorly piped system. The owner wants better fuel consumption, quieter system and better hot water performance.



My big problem is around the indirect, an e-mail from the manufacturer told me don't cold start the boiler. If I keep the triple aquastat installed and maintain a system low temperature will I have much fuel savings by switching to an indirect? For a two zone series loop system with BB fin-tube would a ODR make much sense?

icesailor

Cold Boilers:

That boiler looks like a New Yorker steel boiler. Don't run it as a cold start. It is also a dry base boiler.

What's wrong with the tankless? If it works, put in a storage tank and you can run the boiler with the existing controls and have the operating control at 140 degrees.

This boiler replaced a New Yorker that I think is what you had, with a water heater as a storage tank. The "Indirect Coil" is inside the boiler. The only piping is between the tankless coil in the boiler and the water heater.

Whatever you do, don't run it cold. The seal around the block and base will fail. The savings in money will come from being able to run the boiler at a lower temperature like 165 degrees for the high limit.

Are you in Canada? Granby's are sort of a Canadian boiler.

Hilly

Is this right?

I went searching the forum and found quite a few of your old post. I don't know if you changed your way of doing it, but it appears that I cannot grasps your connection setup, it seems your picture here is a little different than you'd explained it in the past.



1) Circ line (from HWT drain) -> CW inlet on Tankless coil

2) CW (city feed) -> tee's in downstream of circ line and will feed CW inlet (coil) also

3) HW outlet on tankless coil -> pipes into CW inlet on top of hot water tank.

4) HW outlet on HWT -> pipes into HW distribution for the household



?'s: > Should the cw(city) then have a check valve on it?

How would I size the pump? would I be looking at support the 5gpm this coil boosts?

I know you say 006 in many of your post but would it just be a matter of getting your piping loss and finding something to support the GPM? This isn't for myself and I don't want to have any return visits attempting to tweak things.

Triple AquaStat can then be set at 150/170 with the dif on 10?



Note: the reason I'd considered the indirect was because the boiler required a full re-pipe anyway to get rid of all the noise and air problems so I thought it was a simple solution.



Thanks for your info ice sailor

icesailor

Check Valves:

I think you have it correct.

There is a check valve on the top of the tank where the heated water from the coil goes into the cold water inlet of the water heater. It moves the heated water down through the dip tube for dispersal in the lower 1/3 of the tank.

It doesn't matter what the GMP flow is for the circulator. It is a cheap bronze circulator that I have used for over 30 years.

You do NOT have to change any heating pipes.

Look at it this way.  Pipe up a water heater like it is a stand alone water heater. Connect the bottom of the water heater into the cold side of the tankless. Install a circulator and pump it TOWARD the coil. Take the outlet side of the coil and connect it into the cold water feed into the water heater.

That was a replacement. I usually installed a IPS check valve and a union above the circulator so I could disconnect it to change it and not have to solder it. Its the same as a "Side Arm" heater on a Brown Bros. copper storage tank installed in the old 3 decker houses in Boston

I don't think that 006B (Bronze) circulators are available anymore because of lead content. Taco makes the for the same price in Stainless Steel.

heatpro02920

I do it a little different...

I have had good luck with using the grundfos recirc timer pumps on the tankless, it allows a little savings not heating the storage tank while they sleep or are away depending on schedule.... plus they use very little electricity...

Hilly

the re-pipe will happen anyway.

I am repiping the near boiler piping anyway. Circ is on return, manual air vent on suction side with 5', no isolations to purge each loop, no bfp, make-up water is somewhere funny too, cushion tank without 3/4 pipe, without extol tank fitting of any sort, no air separator or line scoop, it's a two zone; zone way setup, that has a flow check that makes a massive amount of noise, and one zone is a split return with no balancing.



So the original thought from the homeowner was could I make his system more quiet… after the fact he'd asked about adding better hot water… Thats when I was curious about the indirect. But as it stands I'll probably keep that simple and utilize the existing coil like you have suggested.

icesailor

Old dogs:

Your boiler sounds like it was piped like most boilers were piped. The way I was taught and most all boilers I have installed and piped were installed. None of then EVER had the plethora of problems I see with all these exotic piping schemes. I'm not saying that exotic piping schemes are not correct or worthless. But maybe some are overthought? The boiler I have shown has run flawlessly for over 20 years. It uses a standard old fashioned Amtrol cast iron air scoop with a float vent above it and a Amtrol #30 Extrol tank. Followed by a B&G SA 1 1/4" flow check. The check does not rattle. There are 5 taco 572 zone valves. If the check rattles, does it rattle when ALL the zones are calling or just one? It could be that the circulator is too big. They often are now days. There's a reason that the Taco 007 circulator is still the top selling circulator. That you will find more of them in a supply house bin than any other model or brand. There must be a reason.

In the last house I built, I/we hired out the whole job to a contractor. I didn't have the time to do it myself. The contractor hired a reputable plumbing contractor. They used what I told them I wanted. A Weil-McLain WTGO-3. They mounted the circulator on the supply outlet. They used a Amtrol #3000 I" air scoop kit. From the time I moved in (2000) to the time I sold it, I never once had a cover off to get at a air vent. I never had a blocked zone from air. I decided to install a WILO smart circulator because of a small zone. It didn't work any better that the 007, it just made me feel good about the technology.

I'm part German. It is said that we Germans love technology for technology's sake. That's true. We also like making money. I sold what people would buy.

"Say, you need a new circulator. The 15 year old 007 one is locked up and leaking".

How much?

$ &&&.

But, I've used this slick new one that will save you money because it doesn't use so much electricity and has a great big fat, wide flange gasket that doesn't leak.

How much?

$XX &&&.

I immediately see the rollers going in the slot machine eyes. They don't stop on the Jackpot Symbols. The eyes fog over like a glass of ice water on a hot, humid summer day. I get the 007 out of the truck. With the thin O-ring gaskets.

Life is good.

icesailor

two zones?

Two zones with Zone Valves?

Open the flow check to stop the rattle. Zone valves are just motorized flow checks. Unless they are quick acting, and powered through the ZC/ZR connections of the low limit/operating control, they will be open while the circulator(s) are off and flow on gravity. Giving you less hot water availability.