Converting to natural gas boiler: need help!


Old 08-01-20, 07:31 PM
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Converting to natural gas boiler: need help!

Hi guys. In some dire need of help here.

2- family up-down rental property. One of the super-old smith mills oil boilers went. Its has been chugging along the last couple of years, and just finally died. The insides have powdered, and the circulator and related piping are rusted and leaking. Can I fix it? Yeah. Piping fixing and wet blanket work may do it. But it's really just time to go.

I have nat gas in the building, separately metered. So figured why not convert to a direct vent gas system.

Called contractors. Out of 20+ I only got a few calls back. And yes, I called multiple times.
I have 3 quotes. 2 in the 6k range, and one for 10k.

The 2 6k quotes wont return my calls after providing the quotes, accepting terms, giving the start date, and not showing up.

The 10k quote, was a mess. Not itemized, guy keeps trying to sell me a $5000 unit I dont need based upon savings monthly on the bill. However, tenants pay the bill. Not me. So for me, it's nothing. I advised him on that, he wont budge.

Further, he wants to locate the new unit on the opposite side of the basement, 40 feet from the water heater and supply lines.

System is a mono-flow system with convector units for heat, with mono-flow tees on every single feed and return line. Locating the boiler on the other side of the basement just wont work. I addressed these concerns as well, his only response was "I work on commission and wont change my quote, take it or leave it".

Soooo....after weeks of going through this, I'm back at step one. And running out of time before fall.

So I need some help.

Can you guys help recommend a good quality gas direct vent unit, heat only (electric water heater for water so a combi unit is not needed - unless its cheaper) that would be cost effective and good for a rental?

Space is a 2nd floor apartment, 1200 sq ft, mono-flow system with convectors.
Single zone.
Location is northeast.
House is 1920's - 1930's vintage with minimal outside insulation.

Getting someone to do this has been near impossible.

Do you guys think a DIY project is doable?

I have already enlisted the local gas company to do the gas lines and connections, so I wouldn't have to mess with that aspect.

Only the boiler and water connections.

I have some non-professional experience. I've added zones for friends, replaced radiators, etc.

I THINK I can undertake this, but wanted to ask what it all entailed to truly assess the project and situation.

Can anyone comment as to the process, etc?

Can anyone suggest equipment?

And any other advice?

Any help would be appreciated.

I've got 6-7k cash to do this with, ready to jump in.

Thanks all. You've all helped me out immensely before. Hoping you can do it again.

Have a great night!
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Old 08-02-20, 06:05 AM
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Hi, will the gas supplier give you any kind of a deal ? so will when converting from oil.
Old 08-03-20, 10:34 AM
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A DIY job is certainly possible IF you follow the manufacturer's installation instructions. Piping on modulating-condensing boilers is critical.I don't have a favorite brand. Just make sure parts are locally avaiable.
Old 08-04-20, 06:00 PM
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The utility company does provide discounts the form of instant rebates. When questioned, the contractor said they all go to him. I don't get them.

Still looking for someone to do the job.

In the meantime, can you guys point me in the direction of some good instructionals for a DIY project?
Old 08-05-20, 07:55 PM
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A good source for prices and basic info is

Start there and compare installer quotes with the prices.

I am just replacing oil fired 50 gallon water heater with gas for total cost $700

HomeDepot has all kinds of fittings and prethreaded lengths of pipe.

Black 1/2" pipe for gas is easy to work with. No need to cut and thread pipe. For one long critical length bought piece 4" shorter than needed, then assortment of small length nipples to match exact distance needed. For piple thread sealant use old type pipe putty paste, not teflon tape.

Also include a sediment trap:

Last edited by doughess; 08-05-20 at 08:34 PM.
Old 08-06-20, 09:54 AM
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Just a heads up, you can use Teflon tape if it is designed for gas, not the standard white tape it would be yellow.
I would suggest a direct vent cast iron product. Less service and less problems. Much less cost of parts when needed.
Is the reason for moving the boiler was due to venting? Maybe could not vent out the wall where the boiler was.
Old 08-06-20, 02:09 PM
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I think the reason he was moving it was, quite frankly, he messed up.
I took another look at his quote, and the small thumbnail sized reference pictures,, which I glanced over initially, were wrong.
They were of the OTHER boiler and oil tank, for the other apartment. These are in fact located on the left of the basement. These are not getting replaced yet, as they are running perfectly still.

Sonit appears that despite me pointing out which boiler was getting replaced, he messed up.

Good catch too, as if he did the wrong one there would be a serious issue.

I'm considering a Bosch Greenstar unit. Reviews look good..
Watching install videos and reading the pdfs.

Old 08-07-20, 06:05 AM
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I try to avoid wasting money. Old cast iron boilers do not have established life time.

My 60 year old oil fired boiler runs at 6
85% efficiency. Would replace only if developed unrepeatable leaks. Over years have replaced valves, circulators. To modernize, upgrade system added a Tekmar 256 Out Door Reset and auto stack vent. Setup may not look pretty, but works great.

“ zx7ninja: The insides have powdered,” Indicates need for good cleaning.

“zx7ninja: circulator and related piping are rusted and leaking” So just replace them.

If zx7ninja still want gas, pull out oil burner unit and plug in gas conversion units that come with 4" tubes. Back in the 1970's oil crisis I use them for a couple of years. If gas is ever cheaper here will plug them back in.

Last edited by Grady; 08-12-20 at 02:32 PM. Reason: Changed efficiency to 85% per Doughess' request.
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