Best Of

Why are you getting rid of the radiators? Forced-air will never be as comfortable…………….

I think it is piped properly. Closed space T under the boiler:

The installer didn't do themselves a favor with the spaghetti piping plus it is highly unprofessional to leave a setup without check you get heat on all zones.

My hat off to @EdTheHeaterMan for tracing any of the pipes as I couldn't when I looked at this.

I've had issues with triticators clogging on gravity feed conversions. The sludge in the old pipes clogs the gauge and gets stuck. A dirt filter would have been a good idea. Obviously you are getting pressure to the boiler as the relief valve vented (these are set to 30PSI).

You need the boiler tech back and they need to make sure you have heat on all zones before they leave. This is not something the owner expected to figure out. That is part of their job when doing this kind of work. If they have to replace any of the existing pumps, that would be extra work and cost, but if the pumps are fine, getting it all working is part of the job.

Also make sure there is an outdoor sensor installed and a base reset curve configured in the boiler. Without that, you are giving something like 10% of free efficiency up.

More importantly, when only a few zones are calling the flow through the boiler may be inadequate to prevent damage to the boiler.

This is interesting. It appears that the suggested piping design for a zone system using pumps that is on page 28 in the manual was not used. in fact they piped it as I feared and this design may not yield the results that the manufacturer intended. Here is the supply piping from the oil boiler:

This is the closest I can get from the photos. Now in the new boiler piping That was not going to be a cluster of piping behind the new boiler (which in my opinion that IS a cluster of piping) and be installed in accordance with the manufacturer's I/O manual (this is the closest one to what you have) using a primary secondary layout.

You can clearly see that the as built piping is not using a primary secondary piping design here:

In fact this piping design is based on old school direct piping from the supply to the return of each zone. Also I can not see zone D piping in the as built piping. This piping design lends itself to improper hydraulic separation of the zone pumps from the internal boiler pump which may cause a problem in transferring heat from the boiler heat exchanger to the system if for some reason all three (or four) zones call at the same time. All the zone pumps are forcing all the flow of all the zones thru the boiler heat exchanger at the same time.  The primary /secondary piping will create the hydraulic separation that the manufacturer requires for the best operation and longest boiler life.  

If the installing contractor will not make this right, then I would contact the manufacturer's representative, the gas company that is supplying the money for the contractor, and the authority having jurisdiction and lodge a complaint that you believe that the installing contractor did not follow the IO manual and you would like them to put whatever influence they have with that contractor and make them install it properly.   

I hope you followed my recommendations to withhold payment until you are satisfied that the system is operating properly.  Which it is not at this time.