Please refer to our Heating Blog Library for additional details.

Why purchase a pre-built, assembled hydronic (FHW) boiler system?

  • Performance – The top American hydronic products, utilizing the latest technologies to provide the most efficient performance in your heating application.
  • Quality – The historically best performing, readily available components assembled and tested using our proven field assembly methods.
  • Value – As our Motto suggests, “More for Less”. We apply purchasing, assembly and logistics to achieve a maximum benefit. The resultant is a premium product that more than competes with lesser installed products.
  • Delivery – What we engineers refer to as TAT (Turn-Around-Time) is minimized. Whether you are scheduling a future new, replacement or emergency heating project, your system is there when you need it.

Who can benefit from a pre-built, assembled boiler system package?

  • Building Contractors – A performance package, delivered to short interval schedule, very competitively priced and requiring lesser completion skills overall.
  • Heating Contractors – A proven package utilizing common components configured for ease of service. Delivered when you need it – no stock on hand.
  • Plumbers – A sophisticated, aggressively priced high performance product that only requires connection to existing service utilities. No parts chasing – stay on the job.
  • DIY’s (Do-IT-Yourselfers) – Our package “takes all the fun out of it”.  No complex control wiring, piping and system layout.  Just connect to your current utilities, fill with water and fire per our Planning & Installation Guide.  Performance and Price!
  • You, the Customer – Whether you have the DIY skills required or not, by specifying our product package you know what you are being sold as the finished product.  No lesser, prior generation or steel boilers priced to sell!  Then solicit installation quotes.

What’s a DELTA-T™ System?

Simply put, it’s a FHW System that utilizes a single, “smart” circulator to circulate the heated water very efficiently. Liken it to your car. Need more power, you step on the gas, need less, let up on the gas. The “smart” circulator regulates the power of your FHW Heating continuously by maintaining the ideal temperature difference between hot water going to your radiation and when it returns to your boiler under all conditions.
Circulation to any or all of your zones is controlled by the newest high efficiency, low energy ball valves.
The term “Delta” is the Greek letter ∆ used by science representing “difference” and “T” represents “Temperature”. Therefore, Delta-T (∆-T) = Temperature Difference.
As we state in our Delta-T Blog, it’s a terrible system: terribly simple, terribly efficient, and terribly inexpensive.  Follow this link to a more in-depth description.

How do I determine what I will require?

  • Heat Loss Requirement – You must know reasonably well what your building “Heat Loss” (heating requirement) is, preferably by calculation.  Refer to our “Using a Heat Loss Calculator” Blog for more detail.  If replacing a boiler, don’t assume the same size is required by merely reading off the current unit nameplate! Building efficiency improvements (insulation, doors, windows, etc.) have effectively reduced your boiler size requirement over the years – and it was probably generously sized by custom at prior installation.  If your architect/builder/heating-engineer can’t provide a calculation – get it done! TOO BIG IS BAD ENOUGH – TOO SMALL IS EVEN WORSE!
  • DHW (Domestic Hot Water) Requirements – The DELTA-T System™ boilers have no internal DHW Coil provisions as you may currently have!  They are “Water Only” Boilers to attain their efficiencies.  They are however pre-plumbed for Indirect Water Heaters and with controls for field installation, current or future.  The Indirect Water Heater by design provides the ultimate in DHW generation efficiency.  Sizing is typically determined by number of baths, bedrooms, family size and additional DHW requirements.  (You can retain your current separate DHW heater — your choice.)
  • Number of Zones – Specify the number of heating zones (thermostats) required both currently and planned (plus one for DHW).  Detail the initial pipe sizes supplying all of your zones, otherwise 1” Valves are provided.  Residential zones are typically ¾” or 1” supply-piped.  Indirect Heaters typically use 1” fittings.
  • Installation Placement – System Dimensional Details must be qualified for installation compatibility.  A lot of flexibility is afforded in our design.  Height in a lower site can be accommodated by design, before shipment.
  • Access Restraints – Refer to our System Dimensional Detail and determine:
    • Can you get it into the building, and safely?  Check widths and weights in particular.  These systems knock down vertically, so access height is usually not an issue, but weights on stairs can be!
    • Door widths and swings must be qualified.
    • Surface quality across yards, etc.

What services do you offer?

  • Provide contract or personal shipping assistance at our location.
  • Deliver and position system at your location.
  • Provide installation and/or preparation services to the degree your local code authority allows.
  • A Help Line Service.
    Note: A Save Harmless Affidavit is required for other than delivery and placement services.  We cannot know all your local code requirements.  No exceptions.

How do I get it delivered to my location?

All product is shipped F.O.B. Antrim, New Hampshire.  Depending upon your terms of service, differing options are available.  Sales taxes do not apply from our shipping point.

  • Ship only – Common Carrier. Crating charges do apply however. Local Pickup optional.
  • Ship & Position – Designated, dedicated transport. Unit transits on our special dolly & must return, same day.
  • Ship, Position & Assist – Designated, dedicated transport with technician(s).
  • Ship & Install – Designated, dedicated transport (service truck) with technician(s).

What can I expect for fuel savings when replacing my current boiler?

It depends completely upon your current system.  Generally speaking, the older your boiler, the more you will save.  Very significant is adding an Indirect DHW Heater.  This takes advantage of the new “Cold Start” Boiler efficiencies (see our blogs).  Assuming this we have averaged a 40% reduction in heating costs utilizing these boilers, without the ∆T feature!  As a matter of policy however we quote no fuel savings estimates.

Will you provide systems utilizing other than a Weil-McLain Boiler?

No. Our make and model selections are predicated on many years of installation and service histories. Specifically, the configurations of these boilers compliment compact packaging, assembly methodizing, handling, installation, durability and serviceability.


All component manufacture warranties apply. We additionally warrant our assembly workmanship for one year.

What about on-going maintenance and service thereafter?

Weil-McLain maintains a nation-wide Service Referral Program. We also suggest reading our blog entry on “Selecting a Serviceman”.

Terms of Payment?

All system products and services are pre-pay. This is usual and customary in Trade Services.
Note: Pre-payment Methods include ONLY:

  • Cash
  • Certified Check
  • Wire Transfer

Credit Card, PayPal & other Card Services are not accepted.

What about Sales Taxes?

New Hampshire is truly a Tax-Free State. We have no income, applicable sales or excise taxes. Further, the NH Supreme Court recently ruled that a N.H. Franchised Business selling a product inter-state has no responsibility to assess or collect taxes for other Principalities or States.
Therefore, F.O.B. Antrim, New Hampshire.