A Boiler Publication, Not a Boiler Company
Calderwick covers one way of heating a house: hot water and steam moving through pipe. Cast iron boilers standing on basement floors, upright radiators under windows, hot water baseboard running along the toe kick, PEX loops stapled beneath a finished floor. Hydronic heat, the thing that keeps much of the Northeast and Midwest warm from October through April.
That is the entire subject. No roofing articles, nothing about the water heater in the corner except where it touches the heating loop.
Why this deserves a site of its own
On a general plumbing site, boilers get a paragraph before the reader is steered back toward clogged drains, and it shows. Someone trying to find out why one radiator stays cold ends up reading advice written for forced air ductwork, or advice written for British houses, where the boiler hangs on a kitchen wall and heats the shower on demand.
American hydronics behaves differently. A house in Buffalo or Milwaukee has a floor standing unit in the cellar, an aquastat wired into the burner, and often a one pipe steam system installed before the war that still lights every night. Heating oil is a live fuel across New England, which adds a tank, a filter, a nozzle and a yearly service visit gas systems never ask for.
The trade line is different too. Across much of the Northeast, boilers belong to HVAC and oil burner technicians every bit as much as to plumbers, so the partner on the other end of the phone is described here as a licensed heating contractor rather than simply a plumber. A site that files the whole hydronic loop under plumbing miscellany gets that wrong in its first sentence.
The site writes. It holds no license.
Nobody at Calderwick is a licensed tradesperson. Nobody here pulls a permit, opens a boiler jacket or hangs a manometer on a gas valve. The output is text on a screen and a single phone line that puts a caller in touch with people who do the job.
Saying so early matters more on a heating site than most, because everything published here stops at a hard boundary: gas piping, burner tuning, control wiring, flue and venting work, and anything a relief valve exists to protect you from. Those belong to a credentialed professional in the room, not to a web page.
What dialing the number gets you
Nobody at this desk answers (800) 555-0163. The line hands you to a heating contractor licensed for your corner of the state: someone who handles boilers, zone valves and radiators week in and week out, not a generalist meeting one for the first time.
The call opens with questions rather than a quote. What does the pressure gauge read. Is the burner trying to fire, or is nothing happening at all. One cold room or the whole house. Gas, oil or propane. Those answers separate a five minute fix over the phone from a visit that has to happen tonight.
Whatever the price turns out to be, it is that contractor's number on that contractor's paperwork, agreed with you before anything gets replaced. Picking up the phone costs nothing, and nothing gets scheduled unless you ask.
How the site is paid for
Reading here is free, no advertising slots are sold, and no manufacturer or contractor can purchase a kind word. One arrangement covers the cost of the work: where a call turns into a job you agree to schedule, a set referral fee comes back to Calderwick from that contractor.
The contractor settles that fee out of the contractor's own money. It is not a line item on your invoice, not a percentage stacked onto your estimate, and it changes nothing about what the repair costs you. The pull such a setup puts on editorial judgment, along with the guardrails around it, is spelled out under how Calderwick is funded.
Who writes the pages
The name on every page is the Calderwick Editorial Desk. That is not a stand-in for someone we would rather not identify; it is a small group that researches the topic, writes, edits and comes back to the material when something changes. No character in a flannel shirt was invented to sign the articles, no portrait was generated to sit beside a name, and no imaginary decades at the burner are claimed.
First drafts here are produced with AI help, which is better said out loud than discovered later. What follows the draft is the part that decides whether a page ships. Figures get walked back to the agency table, code section or manufacturer sheet they came from. Safety steps are read against the primary document rather than somebody's summary of it. Claims that cannot be checked are deleted instead of softened into a maybe, and judgment calls get tested against how partner heating contractors talk about the same repair. All of that, corrections procedure included, is written down under how pages are checked.
January does not reschedule
A furnace that dies in July is an annoyance. A boiler that quits at midnight in January is a house shedding heat by the hour with pipes at risk before sunrise, and that reality shapes how every page here is built.
So the answer sits in the opening lines rather than three screens below a history of central heating. Checks run in the order a cold and tired person can actually perform them: thermostat and boiler switch first, then the gauge, then the burner. Specifics that would otherwise cost a phone call are stated outright, such as the 12 psi Weil-McLain calls a typical cold fill on a residential hot water system, or the 30 psi at which an ASME rated residential relief valve is built to open. Each page also marks the moment when the sensible next move is the phone rather than another paragraph.
The hardest version of the night, a boiler that will not run at all, is written to be read standing on a basement floor with a flashlight in one hand.
The address bar says something else
This site lives at ammoplumbing.com, and that needs explaining rather than ignoring.
The domain was bought from its previous owner. Before that it belonged to a plumbing company operating in Texas under a similar name, a business Calderwick has no connection to: not the same people, not the same trade, not the same part of the country. We are a publication about boilers and hydronic heat, mostly for houses in the Northeast and Midwest, and we do no plumbing work anywhere.
If you came here looking for that Texas company, you have the wrong place and nothing on this site will reach them. Their phone number, their staff and their service area are theirs, and none of it appears here. Nothing on these pages claims their reviews, their years of trading or their licenses, and the number published here connects to a heating contractor near you, not to them.
Reaching a person
The phone and the inbox lead to different places, and mixing them up wastes a cold evening. (800) 555-0163 is for heat. Email reaches the people who write.
Corrections get answered first. A useful one tells us which page, which line, and what the line ought to say instead; those three things reach the editors at [email protected], and the fix usually lands inside the week. Everything else, where a figure came from, how the partner setup works, whether you may quote a passage, goes to that same inbox, and both routes are laid out in more detail.