{"id":7988,"date":"2026-07-24T12:32:11","date_gmt":"2026-07-24T09:32:11","guid":{"rendered":"https:\/\/axinar.com\/blog\/solar-water-heater-problems-leaks"},"modified":"2026-07-24T12:32:11","modified_gmt":"2026-07-24T09:32:11","slug":"solar-water-heater-problems-leaks","status":"publish","type":"post","link":"https:\/\/axinar.com\/en\/blog\/solar-water-heater-problems-leaks","title":{"rendered":"Solar Water Heater Not Heating or Leaking: 5 Common Problems and What to Do"},"content":{"rendered":"<p>A solar water heater runs quietly for years, until one morning the water comes out lukewarm or you spot damp around the base on the roof. Solar with collectors and a backup electric element is mature technology, but it has its own failure points. Here are the 5 most common problems, what they mean, and the alternatives when replacement makes more sense than repair.<\/p>\n<h2>1. No hot water at all<\/h2>\n<p>First check: was there sun over the last few days? If yes, the cause is usually one of three:<\/p>\n<ul>\n<li><strong>Backup element burned out:<\/strong> solar systems almost always have an electric element for cloudy days. If it burned out and the sun didn&#8217;t top it up, water stays cold.<\/li>\n<li><strong>Thermal fluid in the collectors ran low or has air lock:<\/strong> in indirect collectors, glycol circulates between collector and tank. If it leaked out or air entered the loop, heat transfer stops.<\/li>\n<li><strong>Broken thermostat:<\/strong> the tank thermostat is stuck and won&#8217;t let the backup element switch on.<\/li>\n<\/ul>\n<h2>2. Leak from the base of the tank<\/h2>\n<p>Water drips from the tank base or around collector fittings. Causes:<\/p>\n<ul>\n<li><strong>Tank corrosion:<\/strong> the internal lining (glass, enamel, or 316 stainless) has degraded. Enamel typically fails after 10 to 15 years. 316 stainless lasts longer, but water quality and salinity play a big role.<\/li>\n<li><strong>Aged flange gaskets:<\/strong> the rubber seal around the element flange fails in 8 to 12 years.<\/li>\n<li><strong>Frost damage in collectors:<\/strong> if the thermal fluid is water-glycol at wrong concentration, a really cold night can burst copper piping.<\/li>\n<\/ul>\n<h2>3. Water heats up but runs out fast<\/h2>\n<p>Hot water for one shower, when it used to last three. Causes:<\/p>\n<ul>\n<li><strong>Scale on the element:<\/strong> a lime layer reduces heat transfer. Same happens on internal heat exchangers.<\/li>\n<li><strong>Scale in the tank:<\/strong> usable capacity drops as sediment builds up at the bottom.<\/li>\n<li><strong>Worn tank insulation:<\/strong> starts at 90\u00b0C, drops to 40\u00b0C in 6 hours. Heat loss is worse than normal.<\/li>\n<\/ul>\n<h2>4. Water pressure keeps dropping<\/h2>\n<p>Needs constant refilling from the mains. Possible causes:<\/p>\n<ul>\n<li>Micro-leak at a collector fitting, hard to see because water evaporates<\/li>\n<li>Safety valve opening because pressure hits its trip point (typically 6 bar) on very hot days<\/li>\n<li>Thermal fluid escaping from the closed loop<\/li>\n<\/ul>\n<h2>5. The sun doesn&#8217;t &#8220;reach&#8221; (tank under a roof)<\/h2>\n<p>Apartment building with occupied roof, apartment with only under-roof placement, or a Mediterranean home where the roof is shaded in winter. In practice solar works fine in summer, but from November to February the electric element does almost all the work.<\/p>\n<h2>When repair makes sense vs replacement<\/h2>\n<table>\n<thead>\n<tr>\n<th>Tank age<\/th>\n<th>What to do<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1 to 5 years<\/td>\n<td>Repair. Element, gasket, or thermostat swap is simple and cheap.<\/td>\n<\/tr>\n<tr>\n<td>5 to 10 years<\/td>\n<td>Check for corrosion. Repair if the issue is purely mechanical.<\/td>\n<\/tr>\n<tr>\n<td>10 to 15 years<\/td>\n<td>Replacement usually makes more sense than repair, especially with enamel tanks.<\/td>\n<\/tr>\n<tr>\n<td>15+ years<\/td>\n<td>Full replacement with a new solution, not a patch.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>The alternative: <a href=\"\/en\/solbox-info\">AXINAR SolBox<\/a><\/h2>\n<p>If the roof doesn&#8217;t fit a new solar tank, if collector placement is problematic, or you simply want a solution without plumbing on the roof, <strong>the next step is not another solar water heater<\/strong>. The clean solution is the <a href=\"\/en\/solbox-info\"><strong>AXINAR SolBox<\/strong><\/a>: a PV panel connects to a DC controller that feeds power directly to the electric element of your existing water heater. Hot water from the sun, with no piping, no antifreeze, no collector maintenance.<\/p>\n<h3>Why SolBox instead of another solar water heater<\/h3>\n<ul>\n<li><strong>No plumbing on the roof<\/strong>, zero leak risk over 10 to 15 years<\/li>\n<li><strong>No antifreeze<\/strong>, zero maintenance every 5 years<\/li>\n<li><strong>No inverter, no grid connection<\/strong>, simple 2 to 3 hour install<\/li>\n<li><strong>Works with your existing electric water heater<\/strong> 40 to 200L, no tank replacement needed<\/li>\n<li><strong>3 versions<\/strong> (Light \/ Family \/ Pro) depending on usage<\/li>\n<\/ul>\n<h3>When it fits<\/h3>\n<table>\n<thead>\n<tr>\n<th>Scenario<\/th>\n<th>Solution<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Solar 1 to 5 years old with a small fault<\/td>\n<td>Repair<\/td>\n<\/tr>\n<tr>\n<td>Solar 15+ years, tank leaking<\/td>\n<td>AXINAR SolBox (replacement)<\/td>\n<\/tr>\n<tr>\n<td>Roof occupied or not allowed<\/td>\n<td>AXINAR SolBox on the balcony<\/td>\n<\/tr>\n<tr>\n<td>No grid connection (holiday home)<\/td>\n<td>AXINAR SolBox off-grid<\/td>\n<\/tr>\n<tr>\n<td>New electric water heater, want lower running cost<\/td>\n<td>AXINAR SolBox (no tank change)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div style=\"border:1px solid rgba(221,43,28,.28);border-radius:10px;padding:22px;margin:26px 0;background:rgba(255,255,255,.02);\">\n<div style=\"margin-bottom:14px;\">\n<div style=\"font-family:'Barlow Condensed', sans-serif;font-size:1.35rem;font-weight:700;line-height:1.15;margin-bottom:2px;color:#ffffff;\">AXINAR SolBox<\/div>\n<div style=\"opacity:.85;font-size:.92rem;color:#ffffff;\">Hot water from photovoltaics, with no work on your roof<\/div>\n<\/p><\/div>\n<div>\n<p style=\"margin:0 0 12px 0;line-height:1.55;color:#ffffff;\">SolBox turns your existing electric water heater into a solar one, with a PV panel and a DC controller box. No grid connection. No plumbing changes.<\/p>\n<ul style=\"margin:0 0 14px 0;padding-left:20px;color:#ffffff;\">\n<li style=\"margin-bottom:6px;\">Works with any electric water heater 40 to 200L<\/li>\n<li style=\"margin-bottom:6px;\">No inverter or DEDDIE permit required<\/li>\n<li style=\"margin-bottom:6px;\">Install in 2 to 3 hours by a partner technician<\/li>\n<li style=\"margin-bottom:6px;\">3 versions (Light \/ Family \/ Pro) depending on your needs<\/li>\n<\/ul>\n<p>    <a href=\"\/en\/solbox-info\" style=\"display:inline-block !important;background:#dd2b1c !important;color:#ffffff !important;font-family:Barlow Condensed, sans-serif !important;font-size:.9rem !important;font-weight:700 !important;text-transform:uppercase !important;letter-spacing:1.2px !important;padding:10px 22px !important;border-radius:6px !important;text-decoration:none !important;margin-top:10px;\">Free estimate \u2192<\/a>\n  <\/div>\n<\/div>\n<h2>Request a quote<\/h2>\n<p>Send us a photo of your existing water heater and the site, and we&#8217;ll suggest the right SolBox version with a full installation plan.<\/p>\n<p><a href=\"\/en\/contact\" style=\"display:inline-block !important;background:#dd2b1c !important;color:#ffffff !important;font-family:Barlow Condensed, sans-serif !important;font-size:1rem !important;font-weight:700 !important;text-transform:uppercase !important;letter-spacing:1.5px !important;padding:12px 28px !important;border-radius:8px !important;text-decoration:none !important;margin-top:8px;\">Get an estimate \u2192<\/a><\/p>\n<hr>\n<p><em>See also: <a href=\"\/en\/blog\/convert-electric-water-heater-to-solar-solbox\">Complete guide to converting an electric water heater to solar with SolBox<\/a>, or <a href=\"\/en\/blog\/water-heater-pv-solar-heat-pump-comparison\">PV water heater vs solar vs heat pump comparison<\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A solar water heater runs quietly for years, until one morning the water comes out lukewarm or you spot damp [&hellip;]<\/p>\n","protected":false},"author":16,"featured_media":3670,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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pressure? 5 common causes, what to check now, and when a PV boiler retrofit makes sense.","footnotes":""},"categories":[176],"tags":[],"class_list":["post-7988","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/posts\/7988","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/comments?post=7988"}],"version-history":[{"count":0,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/posts\/7988\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/media\/3670"}],"wp:attachment":[{"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/media?parent=7988"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/categories?post=7988"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/axinar.com\/en\/wp-json\/wp\/v2\/tags?post=7988"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}