Contracting a plumber to connect to new HO-installed home-run manifold and rads?

HomeownerDustin

Would you absolutely say "no" to connecting an existing boiler to a new manifold feedings new rads performed by the home owner? What conditions would you need to see to say "yes"?

Situation:
I'm getting 2 whole-home heat pumps with ductless minisplits for my 2 family home. This should take care of the load to design temp (sized to 5 deg F), but I want to keep one boiler in case of extra cold days when the heat pumps can't keep up and/or when gas is cheaper than running the heat pumps.

My Proposal:
There are currently 2 boilers. I want to remove the 50-year old boiler (Unit A), and keep the 20-year old boiler (Unit B: Burnham 90k BTU, which is still oversized for both units combined).

Option 1:
Plumber adds a zone to Boiler B for Unit A distribution. Keep all distribution and rads/baseboard the same (Unit A is monoflow with old convectors, Unit B is 2 zones, individually in series with baseboards + old convectors). These are all bulky and very unattractive.

Option 2 (preferred):
We remove all the convectors and baseboards from both units. I strategically install new hydronic euro style panel radiators (appropriately sized), and run pex to a single manifold. The plumber than connects the manifold to Boiler B. I'm trying to save on labor costs by doing as much grunt work myself. What would you need to see to say "yes" to a job like this (where the homeowner runs the pex and mounts/connects the rads)?

hot_rod

Option 2 if it is in the budget.
It really comes down to the plumber you end up finding. Also, how busy they are.

I was a one man hydronic company and would welcome a knowledgable, or trainable owner doing the slab insulation, mesh, and tubing for example.

I would meet and access their understanding and technical ability. Leave a piping diagram.

Usually I did the manifold connections and pressure testing before the pour. I would inspect before the concrete was scheduled to confirm all is correct and holding pressure.

Same would apply to plate systems, owners were welcome to fasten up the plates, drill holes, etc.

I don't think there is a one answer to that question.

It is critical that radiators like that have the correct placement regarding holes drilled thru the floor. Not much wiggle room if the holes are not drilled straight and in the correct location. Connecting the pex would be fairly easy if they are compression fittings. Sweat or crimp fittings maybe for the plumber to install?

Mounting needs to be level and plumb and not just sheetrock anchors

Mad Dog_2

The correct attitude is all I need to work with anyone.  It depends how busy guys in your area are.  If things are quiet, like now, you'll have better luck.  Mad Dog 🐕