Replies

1. 
   Tim | Jan 28, 2009 09:33pm | #1

   I don't know about the Lochinvar LNV model. The Lochinvar Double Duty water heaters are the equivalent of the Bradford-White Combi-Cor (both have separate "loops" for domestic water and for heating. they do not mix) units.

   I would ask for detailed specifications on the unit proposed and the unit provided. Compare features, capacities and warranties. IF they are basically like for like, but a different brand (personally I think Lochinvar makes a better unit and I sold both a few years ago), and all else matches, don't push it. If you were promised one unit and gat a "bait and switch" demand corrections immediately.

1. 
   westmich | Jan 28, 2009 09:58pm | #2

   Thanks, Tim. The Lochinvar runs at the sytem at 60 PSI while the combi-coreruns at abou 15 I am told, and evidently they use different pumps for that reason. Don't know what effect that has. Also, the Lochinvar has to be drained before hookup to the radiant system, which suggests to me that they are using the same exact water without a separate chamber.  But I will in fact check as you suggest and see what the details are.

    

1. 
   Tim | Jan 29, 2009 05:40pm | #4

   For a "standard" hot water systems, 60 psi is not required, but I see no reason it would be a problem. 15 psi is more than enough in most systems to prevent flashing and/or pump cavitation (99% of the reason systems are pressurized). Different pumps will not be required. The pump should be sized for the required flow and the resistence of the system. Whether that system is at an avaerage of 15 psi or 60 psi is immaterial.

   IF, as you correctly speculate, the requirement to drain the system prior to making connections indicates that the heating and domestic hot water (DHW) loops are not separate, the answer to your original question is emphaticvally YES. Mixing DHW and heating water is almost always a recipe for disaster. Require the contractor to make ammends.

2. 
   Clewless1 | Jan 29, 2009 03:37pm | #3

   I agree w/ Tim. No issues if you have the same type of heater and very similar specs, you got no particular reason to ask for a switch. But if you don't like a particular spec, you have the right to get what you originally specified.

   How did you specify it to start with? On drawings? In a job scope of work?

1. 
   westmich | Jan 29, 2009 06:35pm | #5

   I was deciding between a small high-efficiency boiler and a combi-core with separate water housings for domestic and heating water. Contractor suggested the Bradford-White combi-core was a good choice because it was a single unit (less space) and had separate compartments.  The contractor gave a written job order with parts and prices and scope of work, which included the combi-core.   Sounded (and still sounds) good to me because the 2 water uses were in distinct compartments.

   To my pleasant surprise, the contractor called me yesterday and apologized that the parts had been switched without notifiying me and that they would be here Friday to switch it all out and install the originally spec'd equipment at no charge to me.  He said he was told by the supplier that the Lochinvar unit had 2 compartments, and he accepted their word.  I interviewed several HVAC contractors for this job and he seemed like he was a trustworthy, stand-up guy and that just was proven to be the case. Character goes a long way.

1. 
   Clewless1 | Jan 30, 2009 05:34am | #6

   Right on ... hope you show your appreciation for what can be a tough situation (for everyone involved).

   Mine is a combicore, too. You need the separation between the two systems. Have a good one!