How to Diagnose Problems with a Hot Water Heating System | Ask This Old House

[Music] how long you been here about six months now okay great looks like the floors have been refinished yes sir a couple of weeks ago i'll take my shoes off thank you how old is this house that was built in the 1950s right someday you'll be able to afford furniture so all of the radiators on this side of the house are are working great okay so here's one here is the original radiant coverage no sir my husband built those wow isn't he and that one's on so that one's working fine yeah so we just have one that's not working and that's right over here okay another radiator cover well done thank you all right so let's see and this radiator the typical 50s radiator that is officially ice cold let's start in the basement great okay richard so what'd you find well you have a forced hot water system when i see radiators like that i know it's either forced hot water or steam and steam has been around since the 30s so it's forced hot water okay decades ago all hot water radio systems operated on gravity the water was heated at the boiler and gently rose up through the supply line and into the radiators on each floor of the house once the heat released into the room the water now colder and heavier fell into a return line and back to the boiler to start the process all over again now when electricity came around in the 20s and the 30s then all of a sudden for convenience people put in a circulator pump to push that water around okay now this house is from the 50s the heating system but the boiler is a little bit newer but there's some consistent things are going to be on any heating boiler i want to just take you through first it has to have a burner to make the water hot this is in this case it's oil it could be gas here's the boiler could be any size and shape okay but it's a vessel to hold the water and then we need to have the right water pressure inside we need enough pressure in the system to be sure there's enough water to fill all the radiators but we don't want so much that becomes dangerous okay so we have city water pressure coming in right here and that's going to be 40 50 maybe 60 pounds but we only want 12 pounds going into the heating system so this is a reducing valve pressure reducing valve stepping the pressure down to the right one here now if i let's just be sure that's working yeah that seems to be working fine and the gauge supports that okay so now as we heat the water up as we heat the water up it needs a place to expand so any hydronic system has an expansion tank inside this tank the top half is filled with water the bottom half is filled with air under pressure and there's a neoprene diaphragm that separates the water and the air as the pressure increases it'll push down on that diaphragm acting like a shock absorber to absorb the pressure okay if this didn't work the net result would be an increase in pressure and this safety device is critically important this is a pressure relief valve that will relieve at 30 pounds pressure onto the floor okay but i can tell you right now that the fill valve is right here that seems to be working okay and i think the circulator pump is circulating because all the other zones work so think about when this house was built it was the 50s second world war it was just ended you've got super highways being built all over the country and neighborhoods are popping up everywhere off of this off those highways much like this neighborhood right and the pressure was really on to keep up with this demand how do you keep building these houses faster and cheaper it was no different in the heating business before the 50s you would have had to run individual supplies returns to every radiator and what they came up with is a thing called a monoflow system if you look carefully you see this you've got one pipe monoflow that goes right around the building right right this is really the equivalent of eisenhower's superhighway in your basement okay they needed a way to use less materials and this did it so you have a set of tees going to each single radiator and here's one that goes up to the radio that's not working right but you can really see the system right here here's this highway the water's moving through this trunk and there's two t's here okay well why would the water ever want to go up through those tees why would it go through the off ramp and go up through the radio well some engineer back in the 50s invented this simple solution this t is a little bit different than this do you see it it's got a square on it it's called a diverter t or a this is cast iron here's a copper version of it that's cut away that let's just see what's going on inside look at this you see the restriction right here yep the water comes through the main trunk right here now that means the water has to go through a smaller opening that makes the velocity increase sort of like closing down a garden hose when that happens it creates some pull right here it's called the venturi effect pulling water down here and mixing in what does that do well if i have a little pull right here it's going to pull water through the radiator well that's going to make water leave from the main highway out here through the local access roads really go through the radiator and then come back right here and beyond the traffic jam with me yes and it made sure every radio got the same temperature the right temperature interesting we know now so far you got the right water pressure at the boiler right we know the circulator pump is working because all the other radiators work okay so we've reduced it now it has to be at some point right here at the radiator let's go check all right so here is our radiator right below us is that main trunk the diverter t's on this side pulling this way which means water is supposed to come up right there through that shutoff effect okay now anytime i see a radio it's supposed to be completely filled with water if any air was in the system it could collect on the top of the radiator so there's always going to be some sort of vent on a hot water radiator that'll allow you to burp it and if there was air out here that's which i don't okay so that tells me i have water here there's not much left this is just a pipe this is just a section of cast iron radiator and now there's a shutoff valve right here well is there a chance there's a restriction here i mean maybe just check this i mean let's see there's an open and a closed not [Laughter] all right i turned available boiler back on we should be able to feel heat in a little bit great but now i want you to see it too look at this here's a smartphone but there's an attachment that's a thermographic camera wow so it should be starting to feel a little bit so look at this so you can see the colors now see from the right hand side look at how it's changing yeah wow warmer and warmer cool so actually no warm you guys are going to be warm all winter oh all right i will leave you the radiator but i'm taking this thank you thanks so much that's unbelievable so why do you think somebody turned that radiator off well i think the radio was right at the base of the stairs i assumed that all the heat went up to the top floor hallway and the previous owner just came along and temporarily closed it off because that is effectively zone control for this radio pretty primitive zone control so do you seriously make that house call go all the way out there and that was the fix yeah on this one but i mean it's a reminder you got to not overlook the simple things i'm always called out when things don't work and you think it's got to be some elaborate mechanical problem right it was just a simple pilot error hey if that's plumbing i got the next one you're probably [Music]

Channel: This Old House

Views: 667,530

Keywords: This Old House, Ask This Old House, DIY, Home Improvement, DIY Ideas, Renovation, Renovation Ideas, How To Fix, How To Install, How To Build, Episode, TV Show, Richard Trethewey, hot water, heating, plumbing, diagnosing problems diagnose, radiator problems, hot water heater, difficult skill level, plumbing 101, plumbing basics, plumbing tricks, house plumbing system, how to plumb a house

Id: gOZWyZMOASA

Length: 7min 28sec (448 seconds)

Published: Mon Jan 30 2017