Old DWH and Boiler. Should I consider Combination Boiler?

AlwaysLearning2024

Hi everyone,

I have a Weil CG-8 series 11 (245,000 BTU) boiler installed in 1991 for the hydronic heating system with fin tubbed recessed heating elements and a Ruud Pacemaker PR75-70N hot water heater which is 20 years old.

Both are working fine yet I know I may be on borrowed time (especially with the water heater).

This system is in a 4-family apartment building.

I live in Cincinnati with some winter months and hard water.

When it does come time to replace either system, is a combination boiler a good fit for my application?

Thanks for any help!

EBEBRATT-Ed

What you have is not bad. You could replace with the same thing.

If you want to go high efficiency, you could go with a MOD CON boiler. It will save you some money on fuel but balance that against a boiler life of about 15 years and replacement parts are $$, you have to get them serviced every year. In addition some MFGs make them obsolete in 10 -15 years parts may not be available. But they are really nice boilers if installed properly. Quiet, smooth running and the flame modulates from low to high fire. You can also hook them up with outdoor air reset which saves fuel.

Don't believe the claims of 95-97% efficiency. In your case with fin tube, you need higher water temp. 95-97% is for systems that can run lower temperature.

Now the most important thing is to figure out the right size boiler and the right contractor. There are a LOT of hacks in the business.

You want to have a heat loss done on the building very important. Most contractors won't do them but they should. Don't let them size it off the old boiler. Insist they install the boiler in accordance with the MFG instructions. Get a decent boiler like a Lochinvar, Viessmann and HTP are popular for mod cons. Peerless, Weil McLain or Crown for a Cast Iron Boiler.

For HW You can stay with a gas fired tank or install an indirect water heater to heat from the boiler.

Do not buy a Combi they are trouble.

Others will comment with differing opinions

AlwaysLearning2024

https://forum.heatinghelp.com/discussion/comment/1804266#Comment_1804266

Thank you! Very helpful! Is a heat loss calculation a service that can be purchased or is this part of the quoting process with a qualified technician?

EBEBRATT-Ed

The heat loss should be part of the quote but don't hold your breath. You can do your own. I would recommend you do one anyhow to protect yourself when some contractor comes in with a crazy boiler size.

Mad Dog_2

Expect to pay a nominal fee for someone to do a heatloss, it will take a few hours. Mad Dog