Lurker - Advice Needed (Replacing Oil Boiler/Hot Water) - HVAC-Talk: Heating, Air & Refrigeration Discussion

GeorgeCT · #1 10-01-2009, 09:29 AM

(Sorry so long)
Hi guys, I've been lurking here trying to learn as much as I can and now ready for some advice from the pro's.

This is my situation...

Living in a Cape Code style home (finished attic) built in 1954 where an oil fired American Standard boiler was installed (No. WO 351 Series 3b J3), it's a hot water system using cast iron radiators through out the house, uses one zone for the whole house and is located in Southern Connecticut.

When we bought the house, we changed the tankless hot water to (I guess it's called) an aqua booster, where hot water is circulated through the tankless coil and into a 30 gallon storage tank.

The boiler at 55 years old, has worked great for the over 20 years we've been at this house with hardly any issues and it's been maintained very well.

We just started having issues this past summer with a slow leak in a pipe connecting to the steal expansion tank. Our oil company (who maintains the system) replaced the pipe and tank with the new bladder type expansion tank.
I noticed the pressure in the boiler (normally between 16-18 PSI) would keep rising (25 PSI) to where it would let go of water out the pressure release valve, so the oil company thinks there could be a pin hole leak in the coil letting water seep into the boiler.
(We came to this conclusion because even with the water tuned off to the auto feed valve, the pressure still slowly rises to the point where it will release).

So now I'm looking to replace the whole system...it's time.

My oil company gave me a quote on a Weil McLain boiler and indirect fired hot water tank. This was my cheapest quote.
("Weil McLain WTG04 w/Carlin burner, Taco 007 circulator, flow check valve, Extrol tank, auto feed, back flow preventer, thermal switch, air scoop, hi-vents, low water cutoff, isolation circulator flanges, main purge valve, smoke pipe, oil line, and all other plumbing and electrical work to complete job.")

Getting a HVAC guy to show up is difficult but have gotten some estimates and they are pretty much in the same ball park.
I'm already leaning toward one local HVAC company that was very through in explaining my options.

The HVAC company I choose for the install would be go to guy for everything heating related, not the oil company. The oil company would just deliver the oil and that's basically it.

Here's where I need some input.

The HVAC guy I'm leaning towards suggested (along with some system names I mentioned to him)...

1. System 2000 with either glass lined or stainless steel 40 gallon storage tank (price reflective), hot water mixing valve, flex able oil lines, low water cut off, boiler feed/back flow preventer, air removal system/expansion tank, operational & safety controls.

2. Buderus G115WS, Riello burner, w/Logamatic 2107 controller and matching LT-160 (42 gallon tank) with mentioned additions as above.

3. Burnham MPO w/SuperStor stainless steel (SSU45) indirect with mentioned additions as in option 1. (this was my cheapest option but not by much).

My preference is the Buderus G115WS.
My concern is the LT-160 water tank that sits horizontal with the boiler perched on top. It's nice and neat but if there are issues with either one, dismantling would seem more complicated and a PITA for the HVAC guy.
I would prefer the ST-150 (40 gallon) which is a traditional vertical tank located next to the boiler. From what I've read from the Buderus site, the ST-150 has a faster recovery rate.
Also, raising the boiler up on top of the water tank would make the flue to chimney equal to or higher than the current flue in place.

So basically I'm asking is what system do the pro's like and like to work on?
Are my concerns about the LT-160 vs. ST-150 tanks legitimate?

Thanks in advance to any input you can offer.

heaterman · #2 10-01-2009, 12:43 PM

First, question, did they install the proper size expansion tank. If not, that is the reason for the higher pressure in your current system. Cast iron radiators account for alot of system water capacity so proper sizing of the expansion tank it important. I am a Weil McLain dealer, pass on the Weil McLain oil boiler. My First choice for an oil boiler would be the Buderus with my second being a Burnham.

GeorgeCT · #3 10-01-2009, 01:50 PM

I've questioned the sizing of expansion tank to our oil company a few times since the installation and he assured me it was the right size (Extrol 30).

Which made sense because I was releasing water from the old steel expansion tank more and more frequently.

heaterman · #4 10-01-2009, 04:11 PM

Question 2. What is the pressure of the boiler when it's cold?

GeorgeCT · #5 10-01-2009, 04:22 PM

The pressure never goes down or fluctuates now.

The boiler low temp (right now) is like 150F with a 15 differential.
So when it cools it fires for 5 minutes and turns off. The temp will continue to rise to near 170F then slowly falls. The pressure doesn't change with temp.

I can release the pressure to about 10 PSI but it slowly rises to 25 PSI in about a 24 hour period where then it releases via the pressure release valve. It doesn't pour out, just drops come out.

Noel Murdough · #6 10-01-2009, 04:30 PM

Tankless coil in the boiler likely has a pinhole in it.

GeorgeCT · #7 10-01-2009, 04:42 PM

Quote:

Originally Posted by Noel Murdough

Tankless coil in the boiler likely has a pinhole in it.

Yep...that's what the oil company thinks it is too.

Noel Murdough what do you think about my 3 sanarios for replacement and my concerns for the Budarus water storage tank? (boiler perched on top of tank vs. side by side for serviceability).

GeorgeCT · #8 10-02-2009, 11:15 PM

Anyone have any imput reguarding the LT-160 vs. ST-150 water tank?

GeorgeCT · #9 10-13-2009, 09:20 AM

Well I choose my HVAC company and I'm going with the Buderus G115WS, with Logamatic 2107 and ST-150 (40 gal) indirect water tank and Riello burner.
Everything new from floor to ceiling.

My HVAC guy seems great and spent a lot more time with me than any of the other companies that came by for a quote. He's been to the house three times already taking notes and measurements answering questions and sharing information.
I totally feel comfortable with him and he's not just a front man, he'll be here most of time during the install.

The installation is due on the 26'th of October.

Any suggestions on a simple heat only non-programable thermostat...Buderus Room Sensor, Honeywell Digital Round, Honeywell Classic Round (analog) or thermostats to stay away from?

subcooler-65 · #10 10-13-2009, 12:00 PM

The Buderus room sensor is for a constant circulation type system.....Any digital thermostat would work fine.
That's a nice set-up your having installed, you wont be disappointed.

beenthere · #11 10-13-2009, 12:16 PM

If your current boiler has a PRV.
And the manual valve to it is open. It could be the PRV is bad, and bleeding through.

I would shut the manual valve to it off. And just see if thats the problem.

subcooler-65 · #12 10-13-2009, 12:32 PM

Quote:

Originally Posted by beenthere

If your current boiler has a PRV.
And the manual valve to it is open. It could be the PRV is bad, and bleeding through.

I would shut the manual valve to it off. And just see if thats the problem.

The OP stated this was done in his first post.

beenthere · #13 10-13-2009, 12:37 PM

Quote:

Originally Posted by subcooler-65

The OP stated this was done in his first post.

Its a long post. I missed that. thanks.