/ News & Press / Video / How to Install a Combination Boiler_Water Heater _ Ask This Old House
How to Install a Combination Boiler_Water Heater _ Ask This Old House
WEBVTT Kind: captions Language: en
00:00:05.700 now your heating system is a forced 00:00:09.12000:00:09.130 hot-water heating system in this case 00:00:10.56000:00:10.570 you've got a convector in each room now 00:00:12.15000:00:12.160 convector has heated water comes up 00:00:14.73000:00:14.740 through a pipe right here passes through 00:00:16.80000:00:16.810 this fin heat exchanger and heats up the 00:00:19.56000:00:19.570 air these things are fine we don't have 00:00:21.41900:00:21.429 to do a thing up here although our works 00:00:23.42900:00:23.439 gonna be down in the basement okay now 00:00:27.57000:00:27.580 your heating system has pretty much been 00:00:29.40000:00:29.410 the standard package around these parts 00:00:31.34900:00:31.359 for the last 60 years it's not exactly 00:00:33.15000:00:33.160 new technology this is a gas-fired 00:00:36.13900:00:36.149 cast-iron heating boiler there's a 00:00:38.61000:00:38.620 burner underneath and that heats up a 00:00:40.22900:00:40.239 big block a cast iron right here that's 00:00:42.09000:00:42.100 filled with water all the flue gas goes 00:00:44.16000:00:44.170 up through this pipe right here into the 00:00:45.77900:00:45.789 chimney now the thermostat comes on 00:00:47.72900:00:47.739 upstairs it brings on the burner but it 00:00:49.83000:00:49.840 also brings this circulator pump on to 00:00:51.84000:00:51.850 send the heated water up through those 00:00:53.40000:00:53.410 convector ZUP stairs it works now one 00:00:56.61000:00:56.620 thing I do notice is right here this 00:00:58.77000:00:58.780 thing is rated for a hundred and fifty 00:01:00.54000:01:00.550 thousand BTUs so what does that mean it 00:01:03.02900:01:03.039 means it's really big this would be good 00:01:05.76000:01:05.770 for a house that's about 3,000 square 00:01:07.53000:01:07.540 feet I have under a thousand right we 00:01:09.72000:01:09.730 could actually heat your neighbors next 00:01:10.98000:01:10.990 to neighbors I don't think I know all 00:01:12.30000:01:12.310 right but that's not unusual we see this 00:01:13.86000:01:13.870 happen all the time people have tended 00:01:15.18000:01:15.190 to over size to be safe and that's 00:01:16.92000:01:16.930 inefficient now that's for heating of 00:01:19.02000:01:19.030 the house you have a separate system 00:01:20.85000:01:20.860 right here for making hot water for the 00:01:22.35000:01:22.360 faucets there's a gas-fired tank type 00:01:24.21000:01:24.220 water heater burner right here heats up 00:01:26.79000:01:26.800 a big tank of water right here 40 00:01:28.62000:01:28.630 gallons of water this thing's on 24/7 00:01:31.26000:01:31.270 every day whether or not you hear or not 00:01:33.18000:01:33.190 to make hot water the fact is both of 00:01:35.55000:01:35.560 these systems they work you have heat 00:01:37.32000:01:37.330 give hot water and a fuel head and 00:01:38.73000:01:38.740 continue to go up we'd probably just 00:01:40.08000:01:40.090 keep doing this way forever right well 00:01:42.03000:01:42.040 we want to do today is to eliminate the 00:01:43.26000:01:43.270 boiler in the water heater with one 00:01:44.55000:01:44.560 device which combines heating and hot 00:01:46.35000:01:46.360 water much more efficiently say a little 00:01:48.36000:01:48.370 Barry Colin hey Barry hi how are you 00:01:50.46000:01:50.470 Barry and his crew helping us with the 00:01:51.75000:01:51.760 installation today what do we got what 00:01:53.91000:01:53.920 we have here is we have a gas-fired 00:01:56.25000:01:56.260 combination boiler and it provides both 00:01:58.80000:01:58.810 heat and hot water to the house and what 00:02:01.80000:02:01.810 we call it as a combi so this one small 00:02:04.41000:02:04.420 units gonna replace both of those yeah 00:02:06.21000:02:06.220 let me show you how it works it looks a 00:02:08.94000:02:08.950 little daunting but let me demystify it 00:02:10.80000:02:10.810 a little bit before you had 10 gallons 00:02:13.31900:02:13.329 of water and a cast-iron block now you 00:02:16.33900:02:16.349 one gallon of water inside this 00:02:18.05000:02:18.060 stainless steel block here's that 00:02:19.97000:02:19.980 circulator pump like you had before 00:02:21.55900:02:21.569 which pushes the water through to be 00:02:23.27000:02:23.280 heated inside this block it goes out to 00:02:26.50900:02:26.519 your convector x' clears up its heat to 00:02:28.36900:02:28.379 upstairs comes back cooler and to be 00:02:30.19900:02:30.209 reheated so that's your basic boiler but 00:02:32.36000:02:32.370 it's much more efficient where 00:02:34.25000:02:34.260 difference is this it can make domestic 00:02:36.25900:02:36.269 hot water see the shiny thing right here 00:02:38.08900:02:38.099 with the orange and silver this is 00:02:40.36900:02:40.379 actually a very ingenious flat plate 00:02:42.55900:02:42.569 heat exchanger now this is a series of 00:02:44.86900:02:44.879 plates that are stacked on top of one 00:02:46.72900:02:46.739 another boiler water goes in this 00:02:48.92000:02:48.930 direction through every other plate 00:02:50.59900:02:50.609 polar water a cold water comes the 00:02:53.27000:02:53.280 opposite direction through the other 00:02:54.61900:02:54.629 place now the boiler water never touches 00:02:57.02000:02:57.030 that potable water okay but what happens 00:02:59.42000:02:59.430 is the heat from the boil water is given 00:03:01.09900:03:01.109 up to that cold water thereby making hot 00:03:03.80000:03:03.810 water up at your faucets all right 00:03:05.65900:03:05.669 what's nice about this is this burner 00:03:07.72900:03:07.739 doesn't come on to make hot water for 00:03:09.74000:03:09.750 the faucets unless you open up the 00:03:11.53900:03:11.549 faucet which means you don't use 00:03:12.64900:03:12.659 anything if you're not using the hot 00:03:13.87900:03:13.889 water and there's no tank wow that's 00:03:15.74000:03:15.750 amazing it's pretty cool now bearing is 00:03:17.80900:03:17.819 crew have done a good job you've got a 00:03:18.92000:03:18.930 lot of stuff done here you got plywood 00:03:20.47900:03:20.489 the hangers and up I see gas piping 00:03:22.67000:03:22.680 water piping we ready put this out sure 00:03:24.43900:03:24.449 all right okay you got it 00:03:36.71000:03:36.720 okay good now one of the things about 00:03:39.66000:03:39.670 these units they're so efficient that 00:03:41.70000:03:41.710 there's not much left in the flue gas 00:03:43.29000:03:43.300 except a little bit of temperature and a 00:03:45.03000:03:45.040 little bit of water so we really can't 00:03:46.62000:03:46.630 go into the old-style chimney we have to 00:03:49.41000:03:49.420 actually vent to outside so we're going 00:03:51.24000:03:51.250 to need two holes to the outside one is 00:03:53.46000:03:53.470 for the flue gas to go outside the other 00:03:55.71000:03:55.720 is for combustion air the air to be 00:03:57.30000:03:57.310 burned to come inside now we just make 00:04:19.59000:04:19.600 up the PVC connections 00:04:31.20000:04:31.210 can you turn it in twist it in that's 00:04:38.23000:04:38.240 good well it turns out that this side of 00:04:43.30000:04:43.310 the building is really a good location 00:04:44.52900:04:44.539 for the side wall venting you can see 00:04:46.65900:04:46.669 the intake right here here's the exhaust 00:04:48.93900:04:48.949 each of them are going to have a screen 00:04:50.49900:04:50.509 to keep out birds and bugs 00:04:51.85000:04:51.860 okay now the codes have clear rules 00:04:53.49900:04:53.509 about placement it wants to be above the 00:04:55.99000:04:56.000 snow line so the intake wouldn't get 00:04:57.87900:04:57.889 blocked by snow which it's fine 00:04:59.80000:04:59.810 the other is the exhaust cannot be 00:05:01.93000:05:01.940 within 12 inches of a window so that's 00:05:03.70000:05:03.710 fine and finally it needs to be no 00:05:07.02900:05:07.039 closer than one foot between the intake 00:05:08.98000:05:08.990 and the exhaust you don't want to bring 00:05:10.36000:05:10.370 flu products back into degree burn ah 00:05:12.10000:05:12.110 perfect location great all right Barry 00:05:16.21000:05:16.220 the venting is completed now yeah all we 00:05:18.15900:05:18.169 got to do now is the piping all right so 00:05:19.93000:05:19.940 piping that means hot and cold piping 00:05:22.02900:05:22.039 right here we also have the supply and 00:05:24.10000:05:24.110 return piping to the heating system 00:05:25.87000:05:25.880 right here and the gas connection to the 00:05:28.30000:05:28.310 new combi boiler 00:05:32.93000:05:32.940 you 00:05:58.07000:05:58.080 now in this old boiler you had one speed 00:06:01.20000:06:01.210 the thermostat would call and you would 00:06:02.61000:06:02.620 get 150 thousand BTUs of firing power 00:06:04.86000:06:04.870 with the new device it's got a 00:06:06.54000:06:06.550 modulating gas valve and that means it 00:06:08.97000:06:08.980 can modulate between seventeen thousand 00:06:10.92000:06:10.930 BTUs up to 75 thousand so we can always 00:06:13.47000:06:13.480 match the load that we need so how does 00:06:15.39000:06:15.400 it do that 00:06:15.90000:06:15.910 well it has an outdoor temperature 00:06:17.49000:06:17.500 sensor like this this will mount on the 00:06:19.02000:06:19.030 north side of the building feedback to 00:06:21.06000:06:21.070 the control it will watch that 00:06:22.44000:06:22.450 temperature on the coldest day of the 00:06:23.91000:06:23.920 year you'll fire it up to full fire just 00:06:26.13000:06:26.140 like the old boiler was and give you 00:06:27.84000:06:27.850 plenty of temperature to go through the 00:06:28.98000:06:28.990 convective but on a spring in the fall 00:06:30.75000:06:30.760 which is most of the heating season it 00:06:32.22000:06:32.230 says no we don't need that much water 00:06:33.75000:06:33.760 temperature to still heat the building 00:06:35.70000:06:35.710 and that's where you save energy wow 00:06:37.41000:06:37.420 that's great 00:06:39.17000:06:39.180 all right Emory your new coffee boilers 00:06:41.94000:06:41.950 ready to go excited super excited now 00:06:44.40000:06:44.410 we've got our vent connections done 00:06:45.81000:06:45.820 here's the hot and cold that goes out to 00:06:47.91000:06:47.920 your faucets upstairs okay now this is 00:06:50.13000:06:50.140 the supply returned piping that connects 00:06:52.20000:06:52.210 to your convector x' and here's your 00:06:53.46000:06:53.470 circulator pump that will send that heat 00:06:54.87000:06:54.880 around here's your gas piping that's all 00:06:57.09000:06:57.100 done and electricals done as well okay 00:06:59.10000:06:59.110 so now anytime we burn gas normally 00:07:02.16000:07:02.170 there's a bunch of water vapor filled 00:07:03.90000:07:03.910 with heat that goes up and out of the 00:07:05.13000:07:05.140 chimney this is a condensing boiler and 00:07:07.47000:07:07.480 what that does is it actually extracts 00:07:09.39000:07:09.400 the heat out of the water droplets that 00:07:10.71000:07:10.720 would have been lost up to the 00:07:11.73000:07:11.740 atmosphere use it inside the boiler 00:07:14.07000:07:14.080 makes it much more efficient but we got 00:07:15.99000:07:16.000 to deal with the water that's left over 00:07:18.09000:07:18.100 this is called condensate you can see 00:07:20.31000:07:20.320 right here that it goes to a limestone 00:07:21.63000:07:21.640 neutralizer because that condensate can 00:07:23.73000:07:23.740 be a little bit acidic this is a 00:07:25.35000:07:25.360 condensate pump to pump that water right 00:07:27.15000:07:27.160 over to the sink but we're ready to go 00:07:29.19000:07:29.200 great turn on this button right here all 00:07:32.76000:07:32.770 right Barry once you open up that hot 00:07:33.96000:07:33.970 water faucet I hear it I feel you got 00:07:40.77000:07:40.780 hot water over there oh yeah you have 00:07:42.63000:07:42.640 hot water awesome thank you and now it's 00:07:46.14000:07:46.150 gonna be great you're gonna have plenty 00:07:47.64000:07:47.650 of heat in your house 00:07:48.69000:07:48.700 you'll never run out of hot water and 00:07:50.34000:07:50.350 you're gonna save a ton of energy oh my 00:07:52.38000:07:52.390 gosh and you know what else I'm 00:07:53.28000:07:53.290 realizing this is all of my mechanical 00:07:55.38000:07:55.390 no my little house is got a little bit 00:07:57.54000:07:57.550 that's right let's get this out of your 00:07:58.98000:07:58.990 way 00:07:59.37000:07:59.380 great all right see you later I'm Murray 00:08:01.17000:08:01.180 thank you so much bye-bye bye 00:08:03.68000:08:03.690 you know it seems like a nice little 00:08:06.00000:08:06.010 machine and we were talking efficient 00:08:07.80000:08:07.810 compact you get two devices turned in 00:08:10.14000:08:10.150 the one why isn't this thing at 00:08:11.49000:08:11.500 everybody's house well everybody wants 00:08:12.99000:08:13.000 this and want appliance that can do both 00:08:14.91000:08:14.920 heating and hot water but it has a 00:08:16.71000:08:16.720 limitation and that's really the size of 00:08:18.48000:08:18.490 the house if the house is too big you 00:08:19.86000:08:19.870 don't have enough available power the 00:08:21.90000:08:21.910 other is domestic hot water if you've 00:08:23.16000:08:23.170 got a really big tub 00:08:24.27000:08:24.280 80 to 100 gowns this might not fill it 00:08:26.61000:08:26.620 at the speed you'd like it to be filled 00:08:27.87000:08:27.880 at but you could take a shower all day 00:08:29.25000:08:29.260 long could that's one of the great 00:08:30.30000:08:30.310 things about this now can it heat the 00:08:32.25000:08:32.260 house in produce domestic hot water at 00:08:34.32000:08:34.330 the same time 00:08:35.37000:08:35.380 technically no you know in normal mode 00:08:37.47000:08:37.480 this unit is going to try to heat the 00:08:39.27000:08:39.280 building and so the water will leave 00:08:41.43000:08:41.440 this heat exchanger go through this pump 00:08:43.20000:08:43.210 and go out to the system right here now 00:08:45.27000:08:45.280 if you open up a faucet there's a sensor 00:08:47.25000:08:47.260 in here that will now divert the water 00:08:48.69000:08:48.700 through this valve through that heat 00:08:50.67000:08:50.680 exchanger now it's going to heat up the 00:08:52.44000:08:52.450 hot water and it's going to give 00:08:53.43000:08:53.440 domestic hot water the priority as long 00:08:55.47000:08:55.480 as you have that faucet open you leave 00:08:57.12000:08:57.130 it on for 10 12 15 minutes you'd never 00:08:58.89000:08:58.900 notice it right that you would didn't 00:09:00.12000:09:00.130 have heat upstairs all right 00:09:01.23000:09:01.240 well you are always showing us new stuff 00:09:02.55000:09:02.560 Richard that I - so until next time I'm 00:09:04.80000:09:04.810 Kevin O'Connor I'm richer through it I'm 00:09:06.42000:09:06.430 Tom Silva and I'm Roger cook for ask 00:09:08.52000:09:08.530 this old house I take really long 00:09:10.32000:09:10.330 showers 00:09:10.80000:09:10.810 good adjust for that we're gonna just 00:09:12.15000:09:12.160 you just want a piece yet I'm good
Office location
Engineering company LOTUS®
Russia, Ekaterinburg, Lunacharskogo street, 240/12